Question

The number of moles of NaCl in 3 liters of 3M solution :
(a) 1 (b) 3 (c) 9 (d) 27

Answer 1

answer is 9 because molarity is equal to number of moles of solute upon volume of solution in litre.

Answer 2

Answer:

The correct answer for the given question is (C) 9

Explanation:

A 3M solution of NaCl will have 3 moles of NaCl/liter of the solution.

So to get the number of moles:

$n=\frac{m}{M}$ where n is the number of moles, m the mass, and M the molar mass.

Molar mass of NaCl = 58.44 g/mole

Mass of 3 moles of NaCl $=58.44 \times 3=175.32 \mathrm{g}$

So number of moles n$=\frac{175.32}{58.44}=$ 3.01mol/L

In 3 liters of 3M solution NaCl =$3 \times 3$=9 moles