Question

$1g$ of a complex $\left[\right.Cr\left(\right. H_{2} O \left.\right)_{5}Cl\left]\right.\left(Cl\right)_{2}\cdot H_{2}O$ ( $molecularweight266.5u$ ) was passed through a cation exchanger to produce $HCl$ . The acid liberated was diluted to $1litre$ . The normality of this acid solution is

• A. $5\times 10^{- 3}$ $N$
• B. $7.5\times 10^{- 3}$ $N$
• C. $7.5\times 10^{- 2}$ $N$
• D. $7.5\times 10^{- 1}$ $N$

Answer 1

Answer: (B)

Mole of complex $=\frac{mass}{molar mass}=\frac{1}{266 .5}$
one mole of complex produces two moles of $HCl$
$\left.\left[ Cr \left( H _{2} O \right)_{5} Cl \right] Cl _{2} \rightarrow Cr \left( H _{2} O \right)_{5} Cl \right]^{2+} 2 Cl ^{-}$
Mole of HCl formed $=\frac{1}{266.5}\times 2$
$N_{HCl}= \, \frac{number of moles}{Volume of solution}\times \, n-factor= \, \frac{2}{266 . 5}$
$=7.5\times 10^{- 3}N$