If 4 g of NaOH dissolves in 36 g of H₂O, the molarity of the solution is: (specific gravity of solution is 1 g mL^-1) : 

1.	3 M	2.	3.5 M
3.	2.5 M	4.	2 M

On complete decomposition, the volume of CO₂ released at STP on heating 9.85 g of BaCO₃ (atomic mass, Ba = 137) will be:

1. 1.12 L

2. 4.84 L

3. 2.12 L

4. 2.06 L

The amount of Zinc (atomic weight=65) necessary to produce 224 mL of H₂ (at STP) by the reaction with dilute sulphuric acid will be: 

The number of valence electrons present in 0.53 grams of Na₂CO₃ is:

1. $3.01\times {10}^{23}$

2. $7.22\times {10}^{22}$

3. $12.046\times {10}^{23}$

4. $6.023\times {10}^{23}$

The number of  moles  present in 2.5 litres of 0.2 M  ${\mathrm{H}}_2{\mathrm{SO}}_4$ are:

1. 0.25

2. 0.5

3. 0.75

4. 0.2

 The maximum number of molecules is present in which of the following? 

1. 15 L of $H_2$ gas at STP

2. 5 L of $N_2$ gas at STP

3. 0.5 g of $H_2$ gas

4. 10 g of $O_2$ gas

Two students performed the same experiment separately, and each of them recorded two readings of mass, which are given below. The correct reading of mass is 3.0 g. On the basis of the given data, mark the correct option out of the following statements.

If 500 mL of a 5 M solution is diluted to 1500 mL, the molarity of the resultant solution is: 

1. 1.5 M

2. 1.66 M

3. 0.017 M

4. 1.59 M

Mark the species among the following that contains the highest number of atoms.

1. 4 g He

2. 46 g Na

3. 0.40 g Ca

4. 12 g He

The empirical formula and molecular mass of a compound are ${\mathrm{CH}}_2\mathrm{O}$ and 180 g, respectively. The molecular formula of the compound is -