Suppose the elements X and Y combine to form two compounds XY₂ and X₃Y₂. If 0.1 mole of XY₂ weighs 10 g and 0.05 mole of X₃Y₂ weighs 9 g, the atomic weight of X and Y respectively, will be:

1.	40, 30	2.	60, 40
3.	20, 30	4.	30, 20

Which of the following is dependent on temperature?

A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$. The evolved gaseous mixture is passed through KOH pellets.

Weight (in g) of the remaining product at STP will be:

1. 1.4

2. 3.0

3. 2.8

4. 4.4

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g of magnesium oxide.
The percentage purity of magnesium carbonate in the sample will be: 
(Atomic weight of Mg=24)

A mixture of gases contains H₂ and O₂ gases in the ratio of 1 : 4 (w/w). The molar ratio of the two gases in the mixture will be:

25.3 g of sodium carbonate, Na₂CO₃, is dissolved in enough water to make 250 mL of a solution. If sodium carbonate completely dissociates, the molar concentrations of sodium ion, Na⁺ and carbonate ion, $C{O}_3^{2-}$are respectively:
(molar mass of Na₂CO₃ = 106g mol^-1)

1. 0.955 M and 1.910 M
2. 1.910 M and 0.955 M
3. 1.90 M and 1.910 M
4. 0.477 M and 0.477 M

The volume occupied by one water molecule (density = 1 g cm^-3) is:

1. $9.0\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

2. $6.023\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

3. $3.0\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

4. $5.5\times {10}^{-23}$ $$ ${\mathrm{cm}}^3$

The volume of oxygen gas (O₂) needed to completely burn 1 L of propane gas (C₃H₈)  (both O₂ & propane measured at 0°C and 1 atm) will be:
1. 7 L
2. 6 L
3. 5 L
4. 10 L

An organic compound contains carbon, hydrogen, and oxygen. Its elemental analysis gave C, 38.71%, and H, 9.67%. The empirical formula of the compound would be: