To which group of the long periodic table do the halogen elements belong?
c. Group 17
Explanation: The halogen elements belong to Group 17 of the long periodic table. They are characterized by having seven electrons in their outermost electron shell.
Question ID: 176
Uploaded on: September 18, 2024
Solid state of which of the following compounds is composed of ions?
a. Sodium chloride
Explanation: Sodium chloride (NaCl) is an ionic compound, and its solid state is composed of a regular arrangement of ions (sodium ions and chloride ions) held together by ionic bonds.
Question ID: 177
Uploaded on: September 18, 2024
Which of the following has the highest ability to conduct electricity?
c. Liquid HCl
Explanation: Liquid HCl (hydrochloric acid) has the highest ability to conduct electricity among the options given. This is because it is a strong acid that dissociates completely into ions in its liquid state, providing a high concentration of ions that can conduct electricity.
Question ID: 178
Uploaded on: September 18, 2024
In the first step of fixation of nitrogen which of the following compounds is formed as a result of lightning?
NO
Explanation: During lightning, the high energy breaks the nitrogen (N2) and oxygen (O2) molecules in the atmosphere, leading to the formation of nitrogen monoxide (NO). This is a key step in the nitrogen fixation process that converts atmospheric nitrogen into compounds that can be used by living organisms.
Question ID: 179
Uploaded on: September 18, 2024
Which of the following is the formula of bauxite, ore of aluminium?
c. Al2O3.2H2O
Explanation: Bauxite, the primary ore of aluminium, is commonly represented by the formula Al2O3·2H2O, indicating it is an aluminium oxide hydrate. The specific form of bauxite can vary, but it generally contains aluminium oxide combined with water.
Question ID: 180
Uploaded on: September 18, 2024
Which of the following is the alkyl group containing two carbon atoms?
b. Ethyl
Explanation: The ethyl group is the alkyl group containing two carbon atoms. Its formula is C2H5.
Question ID: 181
Uploaded on: September 18, 2024
Write down the unit of calorific value of fuel. [1] OR Does the temperature increase or decrease with an increase in altitude in the stratosphere? [1]
The unit of calorific value of fuel is Joules per kilogram (J/kg) or kilocalories per kilogram (kcal/kg).
OR
In the stratosphere, the temperature increases with an increase in altitude.
Question ID: 182
Uploaded on: September 18, 2024
Which radiation, coming from the sun, is prevented by the ozone layer from falling on the earth’s surface?
The ozone layer prevents ultraviolet (UV) radiation from reaching the Earth's surface.
Question ID: 183
Uploaded on: September 18, 2024
State whether the following statement is true or false. The volume of gas molecules is taken into consideration in Avogadro’s law.
False.
Question ID: 184
Uploaded on: September 18, 2024
The product of volume and pressure of how many grams of N2 gas is 224 litre-atmospheres at STP? [N = 14]
Number of moles = 224\over 22.4 = 10 mole
Mass = Number of moles × Molar mass
= 10 × 28
= 280 grams
Question ID: 185
Uploaded on: September 18, 2024
Whether the following statement is true or false? The constituent’s particles of a material change position during the conduction of heat through it. OR The width and the cross-section of a conductor remain unchanged, what is the relation between the thermal resistance and thermal conductivity of that conductor?
False
Explanation: During the conduction of heat through a material, the constituent particles (atoms or molecules) do not change their position. Instead, heat is transferred through the vibration or movement of these particles within their fixed positions.
OR
The relation between thermal resistance (Rth ) and thermal conductivity (k) of a conductor is given by:
Rth = L/kA
Question ID: 186
Uploaded on: September 18, 2024
What will be the angle of incidence when a ray of light passes through the centre of curvature of a concave mirror? [1]
When a ray of light passes through the center of curvature of a concave mirror, the angle of incidence is 0 degrees.
Question ID: 187
Uploaded on: September 18, 2024