3. If the rate of diffusion of O2 in to N2 is 2.3 times the rates of diffusion of X in to N2, What will be
the relative molecular mass of X? A. 148
B. 169
C. 64
D. 36
4. All of the following are chemicals used in dry cleaning except one. Which one is exception?
B. Cl₂C=CC₁₂
C. C6H6
D. C17H3COONa+
A. CCl4
5. The substance that depletes the ozone layer and increase the global temperature is
A. Exhaust of petrol engines B. Heavy metals C. Chlorofluorocarbons (CFC) D. Smoke and dust
6. When dilute hydrochloric acid was added to unknown substance a gas that turned lime water to
milky was produced. The unknown substance is.
A. Sulphate B. Nitrate
C. Carbonate
7. Which one of the following salt is normal salt?
A. Zn(OH)CI B. NaHSO4
C. KNO
D. phosphate
D. Ni(OH)Br
8. Which of the following salts is given to people who suffer from anaemia?
B. CuSO
C. FeSO4
D. MgSO
A. KNO₁
9. A petroleum product commonly used as furnace fuel is?
D. petroleum ether
A. gasoline B. kerosene C. diesel oil
10. An alcohol that yield ketones on oxidation are classified as?
A. Dihydric alcohol B. primary alcohol C. Trihydric alcohol D. secondary alcohol



Answer :

1. To find the relative molecular mass of X, we can use the formula:
Rate of diffusion is inversely proportional to the square root of the molar mass.
Given that the rate of diffusion of O2 to N2 is 2.3 times the rate of X to N2:
(Molar mass of N2 / Molar mass of X) = (2.3)^2
Solving for the molar mass of X, we get:
Molar mass of X = Molar mass of N2 / (2.3)^2

2. The exception among the chemicals used in dry cleaning is CCl4 (carbon tetrachloride) because it is harmful to the environment and has been phased out due to its ozone-depleting properties.

3. The substance that depletes the ozone layer and contributes to global warming is Chlorofluorocarbons (CFCs). CFCs are synthetic compounds containing chlorine, fluorine, and carbon that were commonly used in refrigerants and aerosol propellants.

4. When dilute hydrochloric acid reacts with a substance producing a gas that turns lime water milky, the substance is most likely a carbonate. Carbonates react with acids to produce carbon dioxide gas, which turns lime water milky due to the formation of calcium carbonate.

5. Normal salt refers to a salt that is composed of a positive metal ion (cation) and a negative non-metal ion (anion). Among the options given, KNO is a normal salt because it consists of the metal potassium (K⁺) and the anions nitrate (NO₃⁻).

6. People suffering from anemia are often given iron supplements to help increase their iron levels and improve their red blood cell production. Therefore, FeSO4 (iron(II) sulfate) is the salt that is commonly given to individuals who suffer from anemia.

7. Among the petroleum products listed, kerosene is commonly used as furnace fuel due to its relatively higher flash point compared to gasoline and diesel oil, making it safer for use in heating applications.

8. Alcohols that yield ketones upon oxidation are classified as secondary alcohols. Secondary alcohols have a carbon atom attached to two other carbon atoms, which leads to the formation of ketones when oxidized.

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