Match the right column with the left column: [1 × 4]
Left Column
Right Column
1. A transition element.
(a) Aluminium
2. A transuranium elements.
(b) Nickel
3. Reduces Fe₂SO3 at high temperature inthe thermit process.
(c) Tin
4. Present in the alloy bell metal.
(d) Plutonium
1. A transition element. - (b) Nickel
2. A transuranium element. - (d) Plutonium
3. Reduces Fe₂SO₃ at high temperatures in the thermit process. - (a) Aluminium
4. Present in the alloy bell metal. - (c) Tin
Question ID: 66
Uploaded on: September 11, 2024
Draw a Lewis dot diagram of the F2 molecule. (F =9)
Question ID: 68
Uploaded on: September 12, 2024
Why the electrical conductivity of the solution produced by adding little sulphuric acid into pure water is more than the electrical conductivity of pure water ? OR What are the carriers of electricity in the solution during the electrolysis of an aqueous solution of an electrolyte?
The electrical conductivity increases because sulfuric acid dissociates into ions (H⁺ and SO₄²⁻), which carry electric current, unlike pure water.
Or
The carriers of electricity during electrolysis are ions—cations (positive) and anions (negative).
Question ID: 69
Uploaded on: September 12, 2024
Which ion migrates towards the cathode during the electrolysis of aqueous solution of CuSO4 using Cu-electrodes.
During the electrolysis of an aqueous solution of CuSO₄ using copper electrodes, the Cu2+ (copper ions) migrate towards the cathode. At the cathode, these ions gain electrons and are deposited as copper metal.
Question ID: 71
Uploaded on: September 12, 2024
Write down the formula of the black precipitate formed when H₂S gas is passed through an aqueous solution of lead nitrate ? OR What change of colour is observed when H2S gas is passed through an acidified aqueous solution of potassium dichromate?
When H₂S gas is passed through an acidified aqueous solution of potassium dichromate, the solution changes from orange to green due to the reduction of dichromate ions (Cr₂O₇²⁻) to chromium ions (Cr³⁺).
Question ID: 72
Uploaded on: September 12, 2024
Two substances are used in the production of urea, One is ammonia, what is the other?
The other substance used in the production of urea, besides ammonia, is carbon dioxide (CO₂).
Question ID: 73
Uploaded on: September 12, 2024
Mention one use of poly (vinyl chloride).
One use of poly (vinyl chloride) (PVC) is in the production of pipes for plumbing and irrigation systems.
Question ID: 74
Uploaded on: September 12, 2024
Write down the IUPAC name of CH₃CH₂CH₂OH. OR Write down the constitutional formula of an isomer of CH₃CH₂OH.
The IUPAC name of CH₃CH₂CH₂OH is propan-1-ol or propanol.
OR
An isomer of CH₃CH₂OH (ethanol) is dimethyl ether (CH₃OCH₃).
Here is its constitutional formula:
H₃C—O—CH₃.
This is an example of a functional group isomer, where ethanol is an alcohol and dimethyl ether is an ether.
Question ID: 75
Uploaded on: September 12, 2024
What is meant by the calorific value of a fuel? Between coal and diesel which has greater calorific value? [1 + 1]
Between coal and diesel, diesel has a greater calorific value.
Question ID: 76
Uploaded on: September 12, 2024
If the volume of a given mass of a gas at STP is 52 m³ what will be its volume at the pressure of 104 cm Hg temperature remaining constant? OR What will be the volume of 8g of H2 gas (H=1) at the pressure of 4 atmospheres and temperature of 300 K? (R=0.082 litre atmosphere mol-1 K-1)
Initial volume (V1) = 52 m3
Initial Pressure (P1) = 760 cm Hg
Final Pressure (P2) = 104 cm Hg
Boyle's Law: P1V1 = P2V2
V2 = 760 × 52 ÷ 104 = 380 m³
So, the volume of the gas at a pressure of 104 cm Hg, with temperature remaining constant, is 380 m³.
OR
Pressure (P) = 4 atm
Volume (V) = ?
Gas Constant (R) = 0.082 L atm mol-1 K-1
Temperature (T) = 300 K
No of mole (n) = 8/2 = 4 mol
We know, PV = nRT
or, V = nRT/P = 4 × 0.082 × 300 / 4 = 24.6 liters
So, the volume of 8 g of H₂ gas at the given conditions is 24.6 liters.
Question ID: 77
Uploaded on: September 12, 2024
How does the refractive index of a medium depend on the velocity of light? OR What kind of mirror is used in the headlight of a car and why?
The refractive index of a medium (n) is inversely related to the velocity of light (v) in that medium. It is given by:
n = c/v
OR
Concave mirrors are used in the headlights of cars to produce a parallel beam of light covering a longer distance on the road.
Question ID: 78
Uploaded on: September 12, 2024
Mention two advantages of using a CFL lamp over anincandescent lamp.
Two advantages of using a CFL (Compact Fluorescent Lamp) over an incandescent lamp are:
Question ID: 79
Uploaded on: September 12, 2024