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. $3.02\times {10}^{25}$

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

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

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 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 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 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?

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.