Question

What is the number of moles in 42 g of NaCl?

A. 0.61 mol NaCl
B. 0.72 mol NaCl
C. 1.2 mol NaCl
D. 1.8 mol NaCl

Answer 1

Answer : The correct option is, (B) 0.72 mole of NaCl

Solution : Given,

Mass of NaCl = 42 g

Molar mass of NaCl = 58.44 g/mole

Formula used :

$\text{Moles of NaCl}=\frac{\text{Mass of NaCl}}{\text{Molar mass of NaCl}}$

Now put all the given values in this formula, we get the moles of NaCl

$\text{Moles of NaCl}=\frac{42g}{58.44g/mole}=0.718moles=0.72moles$

Therefore, the number of moles of NaCl is, 0.72 moles