Question

$250\, mL$ of sodium carbonate solution contains $2.65\, g$ of $Na_2CO_3$. If $10\, mL$ of this solution is diluted to $500\, mL$, the concentration of the diluted acid will be

• A. $0.01 \,M$
• B. $0.001\, M$
• C. $0.05 \,M$
• D. $0.002\, M$

Answer 1

Answer: (D)

$0.002\, M$

Answer 2

Molarity of $Na_2CO_3$ solution $= \frac{2.65}{106} \times \frac{1000}{250} = 0.1\,M$ $10 \,mL$ of this solution is diluted to $500\, mL$ $M_{1}V_{1} = M_{2}V_{2}$ $0.1 \times 10 = M_{2} \times 500$ $\Rightarrow M_{2} = 0.002\,M$