Question

$25.3\, g$ of sodium carbonate, $Na _{2} CO _{3}$ is dissolved in enough water to make $250\, mL$ of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, $Na ^{+}$and carbonate ions, $CO _{3}^{2-}$ respectively are (Molar mass of $Na _{2} CO _{3}=106\, mol ^{-1}$ )

• A. $0.477\, M$ and $0.477\, M$
• B. $0.955\, M$ and $1.910\, M$
• C. $1.910\, M$ and $0.955\, M$
• D. $1.90\, M$ and $1.910\, M$

Answer 1

Answer: (C)

$\therefore \left[ Na ^{+}\right] =2 \times 0.955\, M =1.910\, M$
$\left[ CO _{3}^{2-}\right]=0.955\, M $