Question

Statement 1 (S1): The formula unit mass of a substance is the sum of the masses of all atoms in a formula unit of a compound.

Statement 2 (S2): The formula unit mass of ${\text{MgCl}}_2$ is 95 u.

• A. Only S1 is true
• B. Both S1 and S2 are false
• C. Both S1 and S2 are true
• D. Only S2 is true

Answer 1

The correct option is C Both S1 and S2 are true

The formula unit mass of a substance is the sum of masses of all atoms in a formula unit of a compound.

The formula unit mass of ${\text{MgCl}}_2$ =
(1 $\times$ atomic mass of Mg) + (2 $\times$ atomic mass of Cl) = (1 $\times$ 24) + (2 $\times$ 35.5) = 95 u

So, both S1 and S2 are true.