Question

If 40 ml of 1.6 M HCl reacts with 60 ml of 2 M NaOH, the mass of NaCl produced is :

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

$\begin{array}{ccccccc}NaOH& +& HCl& \to & NaCl& +& H_{2}O\\ 40\times 1.6& & 60\times 2& & & & \\ =64mmol& & 120mmol& & & & \end{array}$
Calculation of limiting reagent:
1 mmol of NaOH reacts with = 1 mmol of HCl
$\therefore$ 6 mmol of NaOH reacts with = 64 mmol of HCl
Hence, NaOH is the limiting reagent.
Mass of NaCl formed:
1 mmol of NaOH reacts with = 1 mmol of NaCl
$\therefore$ 64 mmol of NaOH reacts with = 64 mmol of NaCl
Mass of NaCl = $64\times {10}^{-3}\times 58.5=3.74g$