If Avogadro number ${\mathrm{N}}_{\mathrm{A}}$, is changed from $6.022\times {10}^{23} mo{l}^{-1}$ to $6.022\times {10}^{20} mo{l}^{-1}$ this would change -
1. The definition of mass in units of grams
2. The mass of one mole of carbon
3. The ratio of chemical species to each other in a balanced equation
4. The ratio of elements to each other in a compound

The number of water molecules is maximum in
1. 18 molecules of water
2. 1.8 g of water
3. 18 g of water
4. 18 moles of water

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?
1. 1:4
2. 4:1
3. 16:1
4. 2:1

When 22.4 litres of H₂(g) is mixed with 11.2 litres of Cl₂(g), both at  STP, the moles of HCl(g) formed is equal to :

1. 1 mol of HCl(g)
2. 2 mol of HCl(g)
3. 0.5 mol of HCl(g)
4. 1.5 mol of HCl(g)

1.0 g of magnesium is burnt with 0.56 g O₂ in a closed vessel. Which reactant is left in excess and by how much? (At. wt. Mg = 24; O = 16)
1. Mg, 0.16 g
2. $O_2$, 0.16 g
3. Mg, 0.44 g
4. $O_2$, 0.28 g

Which has the maximum number of molecules among the following?

1. 64 g SO₂ 

2. 44 g CO₂

3. 48 g O₃ 

4. 8 g H₂

The number of atoms in 0.1 mole of a triatomic gas is (N_A= 6.02 x 10²³ mol^-1)

1. $6.026\times {10}^{22}$

2. $1.806\times {10}^{23}$

3. $3.600\times {10}^{23}$

4. $1.800\times {10}^{22}$