Madhyamik Class 10 Physical Science Solved Paper 2023

Madhyamik Class 10 Physical Science Solved Paper 2023
WhatsApp

Madhyamik Class 10 Physical Science Solved Paper 2023

PHYSICAL SCIENCE

Time: 3 Hours 15 Minutes

(First 15 Minutes for reading the question paper only, 3 Hours for writing) 

Full Marks: For Regular Candidates – 90

For External Candidates – 100

(For Regular & External Candidates)

Only the External Candidates will answer Group ‘E’. Figures in the margin indicate full marks for each question.

Group ‘A’

1. Multiple choice questions.

Four alternative answers are given below for each of the following questions. Write the correct one. [1 × 15=15]

Question 1.1.

Which of the following gases helps in the depletion of ozone in the ozone layer?

  1. CO2
  2. Ar
  3. CFCs
  4. He

Solution

c. CFCs

Explanation:  CFCs (chlorofluorocarbons) are the gases responsible for the depletion of the ozone layer. When released into the atmosphere, CFCs eventually reach the stratosphere, where they are broken down by ultraviolet (UV) light, releasing chlorine atoms. These chlorine atoms then react with ozone (O3) molecules, leading to the depletion of the ozone layer.  

Question 1.2.

What is the value of PV for 4 g of H2 gas at STP? (H = 1)

  1. RT
  2. 2 RT
  3. 4 RT
  4. 0.5 RT

Solution

b. 2 RT

Explanation:

Number of mole (n) = 4/2 = 2

PV = nRT = 2RT

Question 1.3.

How many grams of O2  will be required to make CO2  by burning 12 g of C completely? (C = 12, 0 = 16)

  1. 32 g
  2. 12 g
  3. 16 g
  4. 44 g

Solution

a. 32 g

Explanation:

C   +  O2   ​→  CO2​

12 g   32 g      44 g

From the balanced equation, 12 g of carbon requires 32 g of O2

Question 1.4.

How many types of thermal expansion coefficients are there for a liquid?

  1. 0
  2. 1
  3. 2
  4. 3

Solution

b. 1

Question 1.5.

In the case of refraction of white light through a prism, the light of colour which deviates the least is

  1. yellow
  2. orange
  3. red
  4. violet

Solution

c. red

Explanation:

In the case of refraction of white light through a prism, the light of colour that deviates the least is red.

Question 1.6.

If a reflected ray from a concave mirror makes an angle of 45° with the normal, the angle of incidence will be

  1. 90°
  2. 22.5°
  3. 135°
  4. 45°

Solution

d. 45°

Explanation:

If a reflected ray from a concave mirror makes an angle of 45° with the normal, the angle of incidence will be 45°.

Question 1.7.

What is the unit of conductivity?

  1. mho. meter -1
  2. ohm. meter -1
  3. mho. meter
  4. ohm. meter

Solution

a. mho·meter⁻¹

Question 1.8.

If a current of 0.2 ampere flows through a conductor of resistance 40 ohm, what is the potential difference between the two ends of the conductor?

  1. 0.5 volt
  2. 2 volt
  3. 6 volt
  4. 8 volt

Solution

d. 8 volts

Explanation:

So, the potential difference between the two ends of the conductor is 8 volts.

Question 1.9.

The correct order of penetrating power of α-, β- and γ- rays is

  1. γ > α > β
  2. γ > β > α
  3. α > β > y
  4. β > γ > α

Solution

b. γ > β > α

Question 1.10.

How many elements are there in the fourth period of long periodic table?

  1. 8
  2. 32
  3. 16
  4. 18

Solution

d. 18

Question 1.11.

In the formation of CaO how many electrons are transferred from Ca atom to O atom? (Atomic numbers of oxygen and calcium are 8 and 20 respectively)

  1. 0
  2. 1
  3. 2
  4. 3

Solution

c. 2

Question 1.12.

In the extraction of aluminium by the process of electrolysis, the fused mixture used contains which of the following along with cryolite and fluorspar?

  1. anhydrous aluminium chloride
  2. aluminium hydroxide
  3. aluminium sulfate
  4. pure alumina

Solution

d. pure alumina.

Explanation:

In the extraction of aluminium through electrolysis, the fused mixture used typically contains pure alumina (Al2O3) along with cryolite (Na3AlF6) and sometimes fluorspar (CaF2).

Question 1.13.

For the preparation of N2 gas in the laboratory, the mixed aqueous solution of which of the following two compounds is used?

  1. NaNO2 and NH4Cl
  2. NaNO3 and NH4Cl
  3. NaCI and NH4NO3
  4. NaNO3 and NH4NO3

Solution

b. NaNO3 and NH4Cl.

Explanation:

In the laboratory, nitrogen gas (N2) can be prepared by heating a mixed aqueous solution of:

NaNO3 (sodium nitrate) and NH4Cl (ammonium chloride).

When these two compounds are mixed and heated, they undergo a reaction that produces nitrogen gas along with other products.

Question 1.14.

Which of the following is the formula of zine blende, an ore of zinc?

  1. ZnO
  2. Zns
  3. ZnCO3
  4. InSO4

Solution

b. ZnS

Question 1.15.

Which of the following is an alcohol?

  1. CH3OCH3
  2. CH3CHO
  3. CH3COOH
  4. CH3CH2OH

Solution

d. CH3CH2OH

Explanation:

  1. CH₃OCH₃ – Dimethyl ether (an ether)
  2. CH₃CHO – Acetaldehyde (an aldehyde)
  3. CH₃COOH – Acetic acid (a carboxylic acid)
  4. CH₃CH₂OH – Ethanol (an alcohol)

Group ‘B’

2. Answer the following questions (alternatives are to be noted):

Question 2.1. 

Name a gas present in the atmosphere which is not a greenhouse gas. [1]

Solution

Nitrogen (N2).

Question 2.2.

What is meant by the calorific value of a sample of coal is 30,000 kJkg-1? [1]

OR

Why can wind energy be used for sustainable growth development? [1]

Solution

The calorific value of a sample of coal being 30,000 kJ/kg means that when one kilogram of this coal is completely burned, it releases 30,000 kilojoules of energy in the form of heat.

Wind energy can be used for sustainable growth development because it is a renewable resource.

Question 2.3. 

At a certain pressure the volume of a fixed mass of a gas at a temperature of 0°C is Yo; what will be the increase in volume of the gas, according to Charles’ law, if the temperature of the gas is raised by 1°C keeping the pressure unchanged? [1]

Solution

The increase in volume is Yo/273.

Question 2.4.  

What will be the ratio of a number of molecules present in 1 L of H2 gas and 4 L of CO2 gas at STP? [1]

Solution

1:4.

Question 2.5.

Write whether the following statement is true or false : [1]

The value of coefficient of linear expansion of solid is the same in celsius scale and in Kelvin scale. 

OR

Arrange diamond, iron and silver in the order of decreasing thermal conductivity. [1]

Solution

True.

OR

Diamond > Silver > Iron.

Question 2.6.

Write one use of a convex mirror. [1]

Solution

A convex mirror is commonly used as a rearview mirror in vehicles.

Question 2.7.

A ray parallel to the principal axis of a concave mirror follows which path after reflection by the concave mirror? [1]

Solution

A ray that is parallel to the principal axis of a concave mirror, after reflection, will pass through the focal point (F) of the mirror.

Question 2.8.

If the same potential difference is applied between the two ends of iron and copper wires having the same length and cross section, does equal amount of current flow through the two wires? [1]

Solution

No, equal amounts of current will not flow through the two wires when the same potential difference is applied.

Question 2.9.

Draw I-V graph according to ohm’s law in the case of a metallic conductor. [1]

Solution

I-V graph

IV graph of ohms law

Question 2.10.

Mention one peaceful use of atomic energy. [1]

OR 

Fill up the blank : [1]

γ-ray is ____ wave of short wavelength. 

Solution

One peaceful use of atomic energy is nuclear power generation.

OR

Electromagnetic wave.

Question 2.11.

Match the Right column with the Left column: [1 × 4]

Left column Right column
2.11.1. An alkaline earth metal (a) Fe
2.11.2. The metal which is present in the highest percentage amount in the alloy invar (b) Zn
2.11.3. An alkali metal (c) Ca
2.11.4.  The metal which is given as coating to prevent the rusting of iron (d) K

 

Solution

2.11.1 → c

2.11.2 → a

2.11.3 → d

2.11.4 → b

Question 2.12.

Write whether the following statement is true or false: [1]

The formation of an ionic compound is made possible largely by the formation of a stable ionic network.

Solution

True

Question 2.13.

In the refining of impure copper metal by the process of electrolysis, the mass of which electrode increases? [1]

OR

In the electroplating of gold over silver, what is used as electrolyte? [1]

Solution

In the refining of impure copper metal by the process of electrolysis, the mass of the cathode increases.

OR

In the electroplating of gold over silver, potassium gold cyanide (KAu(CN)2) is commonly used as the electrolyte.

Question 2.14.

Fill up the blank : [1]

During electrolysis, electricity is carried through the electrolyte by ____.

Solution

During electrolysis, electricity is carried through the electrolyte by ions.

Question 2.15.

Mention one reason for the relative chemical inertness of N2. [1]

OR

Of the two substances used for the production of urea one is carbon dioxide, what is the other? [1]

Solution

One reason for the relative chemical inertness of N₂ (nitrogen gas) is its triple bond.

OR

Ammonia (NH3)

Question 2.16.

Which compound is formed by the reaction of atmospheric nitrogen and oxygen as a result of lightning? [1]

Solution

The compound formed by the reaction of atmospheric nitrogen and oxygen as a result of lightning is nitrogen monoxide (NO).

Question 2.17.

Write IUPAC name for CH3CH=CH2 [1]

OR

What is the disposition of the four valencies of carbon in methane? [1]

Solution

The IUPAC name for CH₃CH=CH₂ is prop-1-ene.

OR

In methane (CH4), the four valencies of carbon are disposed in a tetrahedral geometry.

Question 2.18.

Write one use of denatured spirit. [1]

Solution

It is often used to dissolve oils, resins, and other substances.

Group ‘C’

3. Answer the following questions (alternatives are to be noted) [2 × 9]

Question 3.1.

Mention two possible future effects of global warming on environment.

Solution

Two possible future effects of global warming on the environment are:

  • Increased Sea Level Rise: Melting ice caps will lead to coastal flooding and erosion.
  • Extreme Weather Events: Global warming will cause more frequent and intense hurricanes, droughts, and heatwaves.

Question 3.2.

A fixed mass of a gas occupies a volume of 580 cm3 at a temperature of 17°C and a pressure of 750 mm. What volume will the gas occupy at that pressure and at a temperature of 47°C?

OR

Two gases of the same mass occupy at STP the volumes of 4480 mL and 5600 mL respectively. Find out the ratio of molar masses of the two gases.

Solution

V1 ​ = 580 cm3 (initial volume)

T1 ​ = 17°C = 17 + 273.15 = 290.15 K

T2 ​ = 47°C = 47+273.15 = 320.15K

V2 ​ = ? (final volume)

Charles’s Law: V_1\over T_1 = V_2\over T_2

⇒ V2 = V_1\over T_1 × T2

⇒ V2 = 580\over 290.15 × 320.15 = 638.16cm3

OR

Volume of Gas 1 (V1) = 4480 mL

Volume of Gas 2 (V2) = 5600 mL

For Gas 1: n1 = 4480/22400 = 0.2 moles

For Gas 2: n2 = 5600/22400 = 0.25 moles

From relation: M_1\over M_2 = n_2\over n_1

⇒ M_1\over M_2 = 0.25\over 0.2  = 5\over 4

The ratio of the molar masses of the two gases is 5:4.

Question 3.3.

Write Snell’s law of refraction of light.

OR

Write two characteristics of the image of an extended object formed when it is placed in between the optical centre and focus of a thin convex lens.

Solution

Snell’s law

The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant, for the light of a given colour and for the given pair of media.

Mathematical form: μ = sin i / sin r

OR

Characteristics of the Image 

  • Upright (erect) and Virtual
  • Enlarged

Question 3.4.

Write one characteristic of each of electrical heater wire and fuse wire.

Solution

Electrical Heater Wire: Has a high resistance and High Melting Point.

Fuse Wire: Has a low melting point and low resistance.

Question 3.5.

Show by drawing a Lewis dot diagram of CH4 that CH4 is formed by covalent bonds. (Atomic numbers of H and C are 1 and 6 respectively)

Solution

Lewis dot diagram of CH4

Electron Dot structure of Methane

  • Carbon shares one of its four valence electrons with each of the four hydrogen atoms.
  • Each hydrogen atom shares its single electron with carbon.
  • This sharing results in four covalent bonds.

Question 3.6.

Show by the help of a property of sodium chloride that sodium chloride is composed of ions.

OR

Show how ionic bond is formed in sodium chloride. (Atomic numbers of Na and CI are 11 and 17 respectively)

Solution

Sodium chloride (NaCl) conducts electricity when dissolved in water, indicating it is composed of ions. Upon dissolution, NaCl dissociates into sodium ions (Na⁺) and chloride ions (Cl⁻), which are free to move in the solution, allowing it to conduct electric current. This behaviour confirms its ionic nature.

OR

Sodium chloride (NaCl) is formed through the transfer of an electron from sodium to chlorine, resulting in the formation of Na⁺ and Cl⁻ ions, which are held together by ionic bonds.

Electron Dot structure of Sodium chloride

Question 3.7.

Write, with the balanced chemical equation, what happens when H2S gas is passed through an aqueous solution of Pb(NO3)2.

Solution

When hydrogen sulfide (H2S) gas is passed through an aqueous solution of lead(II) nitrate (Pb(NO3)2), a chemical reaction occurs that results in the formation of lead(II) sulfide (PbS) as a precipitate and nitric acid (HNO3) as a byproduct.

Balanced Chemical Equation:

H2S(g) + Pb(NO3)2 ​ (aq) → PbS(s) ↓ + 2HNO3 ​ (aq)

Question 3.8.

In the extraction of metal by the process of electrolysis at which electrode does the following reaction occur ?

M+ + e− ⇌ M (M = Metal)

Is it an oxidation or a reduction reaction? Answer with reason.

OR

Mention one use of aluminium. Why acidic foods should not be kept in an aluminium container?

Solution

The reaction occurs at the cathode during the process of electrolysis.

This is a reduction reaction because it involves the gain of electrons.

OR

One use of aluminium is in packaging materials, such as aluminium foil.

Acidic foods should not be kept in an aluminium container because they can react with the metal, leading to the leaching of metal into the food, which alters the taste and poses health risks due to potential neurotoxicity from high aluminium intake.

Question 3.9.

How is polyethene produced by the polymerisation reaction of ethylene?

OR

How can the following conversion be carried out?

HC = CH → CH3CH3

Solution

Polymerisation of ethylene: Ethylene is liquified at high pressure (1500-2000 atm). In the presence of catalysts such as peroxide, oxygen or chromium oxide and at temperatures 150℃-200℃, a large number of ethylene molecules join to form a white solid called polyethylene or polythene.

nC2​H4​→(C2​H4​​)n

OR

The conversion of ethyne (HC≡CH) to ethane (CH₃CH₃) can be carried out through hydrogenation using platinum (Pt) as a catalyst.

HC = CH + H2 ​ {\overset{Pt}{\longrightarrow}} CH3​CH3​

Group ‘D’

4. Answer the following questions (alternatives are to be noted)

Question 4.1.

What is an ideal gas? What is the effect of the increase in temperature on the pressure of a gas kept in a closed container? Answer with reason. [1 + 2]

Solution

Gases which obey the PV=RT (for 1 mole) equation at all temperature and pressure are called ideal gases.

The pressure of a gas in a closed container increases with an increase in temperature due to the kinetic theory of gases. As temperature rises, gas molecules move faster, leading to more frequent and forceful collisions with the container walls, which raises the pressure.

Question 4.2.

On burning sulfur in oxygen, sulfur dioxide is produced

S + O2 → SO2

For producing 2240 L of SO2 at STP

(i) How many grams of sulfur and (ii) how many moles of O2 will be required? (0 = 16, S = 32) [3]

OR

On burning 480 g of a solid compound in 352 g of oxygen, 320 g of another solid compound and a gaseous compound are produced. If the vapour density of the gaseous compound is 32, how many moles of the gaseous compound are formed? [3]

Solution

Balanced Chemical Equation:

S        +      O2 →     SO2

32 g         1 mol       22.4 L

(i) Amount of S required to produce 22.4 L of SO2 = 32 g

⇒ Amount of S required to produce 2240 L of SO2 = 32\over 22.4 × 2240 = 3200 g

(ii) The number of moles of oxygen required to produce 22.4 L of SO2 = 1

⇒ The number of moles of oxygen required to produce 2240 L of SO2 = 1\over 22.4 × 2240 = 100 mol

OR

Given Data

  • Mass of solid compound burned = 480 g
  • Mass of oxygen used = 352 g
  • Mass of solid compound produced = 320 g
  • Vapor density of gaseous compound = 32

Molar Mass = 2 × Vapor Density

= 2 × 32

= 64

Mass of gaseous compound=480 g + 352 g − 320 g

= 512 g

∴ Moles of gaseous compound = 512/64 = 8 mol

Question 4.3.

Define the coefficient of volume expansion of a solid and write its mathematical form. [1 + 2]

OR

Give one example of each of the thermal expansion of solid, liquid and gaseous substances from everyday experience. [1 + 1 + 1]

Solution

Definition: The coefficient of volume expansion of a solid is defined as the fractional increase in its volume per degree rise in temperature.

Coefficient of volume expansion (γ) = V_2 - V_1\over V_1(θ_2-θ_1)

OR

Examples of Thermal Expansion

  • Solid: Railway Tracks – Railway tracks expand during hot weather, which can cause them to bend or warp if not properly spaced.
  • Liquid: Thermometer – The mercury in a thermometer expands and rises when heated, allowing it to indicate temperature changes.
  • Gas: Inflated Balloon – A balloon filled with air expands and may burst when heated, as the air inside takes up more space due to thermal expansion.

Question 4.4.

In the case of refraction if the angle of incidence is 45° and the refracted ray makes an angle of 60° with the normal, what will be the value of the angle of deviation?

If an object of 6 cm in length is placed at a distance of 2.4 cm in front of a convex lens, the image is formed at a distance of 4.8 cm from the lens. What are linear magnification and the length of the image? [1 + 2]

OR

The velocity of light in the glass medium is 2 × 105 Kms-1 and the velocity of light in water medium is 2.25 × 105 Kms-1. Determine the ratio of refractive indices of glass and water medium.

Solution

Angle of incidence (i) = 45º

Angle of refraction (r) = 60º

Angle of deviation (δ) = i − r

= 45º – 60º = −15º

The negative sign indicates that the deviation is towards the normal.

Given:

Object length (h) = 6 cm

Object distance (u) = – 2.4 cm

Image distance (v) = 4.8 cm

(i) Linear Magnification (m) = 4.8\over -2.4 = -2

(ii) Length of the Image = m × h = – 2 × 6 cm = -12 cm

The negative sign indicates that the image is inverted.

OR

Speed of light in vacuum = 3 × 105 km/s

Speed of light in glass = 2 × 105 Km/s

Speed of light in water = 2.25 × 105 Km/s

μglass = 3 × 10^5\over 2 × 10^5 = 1.5

μwater = 3 × 10^5\over 2.25 × 10^5 = 4/3

Ratio = μglass : μwater = 1.5 : 4/3 = 9:8

Question 4.5.

Write one use of each of the x-ray and ϒ-ray. Mention one harmful effect of γ-ray.

Solution

Uses

  1. X-ray: X-rays are commonly used in medical imaging to visualize the internal structures of the body, such as bones and teeth, helping in the diagnosis of fractures and other conditions.
  2. γ-ray (Gamma-ray): Gamma rays are used in cancer treatment (radiotherapy) to target and destroy cancer cells.

Harmful Effect of γ-ray

One harmful effect of gamma rays is that they can cause DNA damage in living cells, potentially leading to mutations, cancer, or radiation sickness.

Question 4.6.

Two metallic wires A and B of the same length are made of the same material. The radius of wire A is double the radius of wire B. What is the ratio of resistances of the two wires? [3]

OR

There are three 220V-60W electric lamps and two 220V-100W electric fans in the house. The electric lamps are lit for 5 hours a day and the fans are run for 10 hours a day. If the cost per B.O.T unit is Rupees 5, what will be the cost of electricity for 30 days? [3]

Solution

R = ρ l\over a

or,R = ρ l\over πr^2

⇒ R ∝  1\over r^2

⇒ R_A\over R_B = {{r_B}^2\over {r_A}^2

Given: rA = 2rB

⇒ R_A\over R_B = {{r_B}^2\over {2r_B}^2

⇒ R_A\over R_B = {{r_B}^2\over 4{r_B}^2

⇒ R_A\over R_B = 1\over 4

∴ The ratio of resistances of the two wires 1 : 4.

OR

Energy Consumption of the Lamps

  • Power of each lamp = 60 W
  • Total power for 3 lamps = 3 × 60 W = 180 W
  • Daily energy consumption = 180 × 5 hours = 900Wh

Energy Consumption of the Fans

  • Power of each fan = 100 W
  • Total power for 2 fans = 2 × 100 W = 200 W
  • Daily energy consumption = 200 W × 10 hours = 2000 Wh

Total Energy Consumption per Day

= 900Wh + 2000 Wh

= 2900 Wh

= 2.9 kWh

Total Energy Consumption (30 Day) = 2.9 kWh × 30

= 87 kWh

Total cost = ₹ 5 × 87 = ₹ 435

Question 4.7.

Write Faraday’s laws of electromagnetic induction.
Mention one advantage of using a LED lamp over an incandescent lamp. [2 + 1]

Solution

Faraday’s law of electromagnetic induction:

  1. Whenever there is a change in magnetic flux linked with a coil,an emf is induced,which lasts as long as the change inmagnetic flux is linked with the coil changes.
  2. The magnitude of the induced emf is directly proportional to the rate of change magnitude flux linked with the coil.

LED lamps are more energy-efficient as they consume significantly less power and last longer compared to incandescent lamps.

Question 4.8.

There are 92 protons and 143 neutrons in the nucleus of a radioactive atom. If an α-particle is emitted from that atom how many protons and neutrons will be present in the nucleus of the new atom formed? What type of nuclear reaction is the source of energy of stars? [2 + 1]

Solution

After the emission of an α-particle:

  • Protons: 92 – 2 = 90
  • Neutrons: 143 – 2 = 141

The new atom will have 90 protons and 141 neutrons.

The energy of stars is primarily produced by nuclear fusion reactions.

Question 4.9.

Write the contribution of Mendeleef in the creation of the ‘periodic table’. [3]

OR

What is meant by the atomic radius of an atom? Arrange the first three elements C, Si and Ge of group 14 of long periodic table in the order of their increasing atomic radii. [2 + 1]

Solution

Mendeleev’s contributions to the creation of the periodic table include:

  1. Periodic Law: He arranged elements in order of increasing atomic mass and discovered that elements with similar properties appeared at regular intervals (periodicity).
  2. Predictions: Mendeleev left gaps in the table for undiscovered elements and accurately predicted their properties, such as gallium and germanium.
  3. Grouping of Elements: He successfully grouped elements with similar chemical properties into columns, establishing the foundation for the modern periodic table.

OR

The atomic radius of an atom is the distance from the center of the nucleus to the outermost shell of electrons. It represents the size of the atom.

For group 14 elements (C, Si, Ge):

C < Si < Ge

Question 4.10.

Mention two classes of electrolytes. How can they be differentiated?

Solution

Two Classes of Electrolytes:

  1. Strong Electrolytes: Completely dissociate into ions in solution (e.g., sodium chloride, hydrochloric acid).
  2. Weak Electrolytes: Partially dissociate into ions in solution (e.g., acetic acid, ammonium hydroxide).

Differentiation:

  • Strong Electrolytes conduct electricity well due to full ionization.
  • Weak Electrolytes conduct electricity poorly because they only partially ionize

Question 4.11.

Write the balanced chemical equation for the reaction that occurs in the Haber process for the industrial manufacture of ammonia. Write the conditions of the process. [1 + 2]

Solution

Balanced Chemical Equation for the Haber Process: 

N2 (g) + 3H2 ​ (g) ⇌ 2NH3 ​ (g)

Conditions of the Process:

  1. Temperature: Approximately 450°C.
  2. Pressure: Around 200 atmospheres.
  3. Catalyst: Finely divided iron with promoters like potassium and aluminium oxides or molybdenum.

Question 4.12.

A hydrocarbon in the substitution reaction with chlorine in diffused sunlight forms methyl chloride in the first step. What is the hydrocarbon ? Write balanced chemical equation for the first step of the reaction. Mention one use of the hydrocarbon. [1 + 1 +1]

OR 

What is the industrial source of LPG?
Write one use of each of acetic acid and poly (tetrafluoroethylene). [1  + 2]

Solution

The hydrocarbon is methane (CH4).

Balanced Chemical Equation for the First Step:

CH4+ Cl2 {\overset{\text{diffused sunlight}}{\longrightarrow}}  CH3 + HCl

In this reaction, methane reacts with chlorine to form methyl chloride (CH3Cl) and hydrogen chloride (HCl).

Use of Methane:

Methane is widely used as a fuel in domestic and industrial applications due to its high energy content.

OR

The primary industrial sources of LPG (Liquefied Petroleum Gas) are natural gas processing and crude oil refining.

Uses:

  1. Acetic Acid: Used as a preservative and flavouring agent in food (e.g., vinegar).
  2. Poly (tetrafluoroethylene): Commonly known as Teflon, it is used as a non-stick coating for cookware.

Group ‘E’

(For external candidates only)

5. Answer the following questions (any four)

Question 5.1.

The amount of which greenhouse gas in the atmosphere increases by the burning of fossil fuel?

Solution

Carbon dioxide.

Question 5.2.

What is the product of the pressure and volume of 32 g of O2 gas at STP? (0 = 16)

Solution

PV = nRT

= 1 × 0.082 × 273

= 22.4 atm L.

Question 5.3.

What is DC?

Solution

DC (Direct Current) is a type of electric current that flows in a single, constant direction. In a DC circuit, the electric charge (current) does not change direction.

Question 5.4.

By the emission of which radioactive ray from the atom of a radioactive element, no new atom is created?

Solution

γ-rays.

Question 5.5.

Draw the structural formula of a saturated hydrocarbon containing two carbon atoms.

Solution

The structural formula of ethane:

Ethane

6. Answer the following questions (any three)

Question 6.1.

What is the importance of insulators in household wiring?

Solution

Importance of Insulators in Household Wiring:

  1. Safety: Prevents electric shock.
  2. Prevents Short Circuits: Avoids electrical fires.
  3. Efficiency: Reduces energy loss.
  4. Durability: Protects against moisture and corrosion.

Question 6.2.

Whether a concave lens is called a converging or diverging lens? Answer with reason.

Solution

A concave lens is called a diverging lens.

Reason:

When parallel rays of light pass through a concave lens, they diverge or spread out after refraction.

Question 6.3.

Write, with the balanced chemical equation, what happens when dilute sulfuric acid is added to ferrous sulfide.

Solution

When dilute sulfuric acid (H2SO4) is added to ferrous sulfide (FeS), a chemical reaction occurs, producing hydrogen sulfide gas (H2S) which has a characteristic rotten egg smell and ferrous sulfate (FeSO4).

Balanced Chemical Equation:

FeS + H2SO4 ​ →FeSO4 ​ + H2S

Question 6.4.

Give two reasons in favour of using paper for packaging.

Solution

Reasons for Using Paper for Packaging:

  1. Biodegradable: Paper is biodegradable and breaks down naturally, reducing environmental impact compared to plastic packaging.
  2. Recyclable: Paper can be easily recycled, promoting sustainability and reducing the need for new raw materials.

———– End ———–

≫ You May Also Like