224 ml of a triatomic gas weighs 1g at 273 K and 1 atm. The mass of one atom of this gas is:

1.  8.30 × 10^–23 g

2.  2.08 × 10^–23 g

3. 5.53 × 10^–23 g

4.  6.24 × 10^–23 g

In a hydrocarbon, the mass ratio of carbon to hydrogen is 6:2. The empirical formula of the hydrocarbon is:

The total number of protons in 10 g of CaCO₃ is:
(N₀ = 6.023 × 10²³)

1. $3.01\times {10}^{24}$

2. $6.02\times {10}^{24}$

3. $2.01\times {10}^{25}$

4. $3.02\times {10}^{25}$

Two solutions of a substance (non-electrolyte) are mixed in the following manner.
480 ml of 1.5 M first solution +520 mL of 1.2 M second solution. What is the molarity of the final mixture?

1. 1.20 M 

2. 1.50 M

3. 1.344 M 

4. 2.70 M

The density of a 2 M aqueous solution of NaOH is 1.28 g/$c{m}^3$. The molality of the solution is: 
[molecular mass of NaOH = 40 $gmo{l}^{-1}$]

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 concentration of 69% nitric acid (by mass) in a sample with a density of 1.41 g / mL will be-

1. 15.44 mol/L

2. 17.14 mol/L

3. 20.06 mol/L

4. 12.26 mol/L

The mass of ammonia produced when 2.00 × 10³ g dinitrogen reacts with 1.00 ×10³ g of dihydrogen is: 

Which of the following statements about a compound is incorrect?