Question

For the coagulation of $200\text{mL}$ of $A{s}_2{S}_3$ solution, $10\text{mL}$ of $1MNaCl$ is required. What is the coagulating value (number of millimoles of solute needed for coagulation) of 1 litre of a solution of$A{s}_2{S}_3$?

• A. 200
• B. 100
• C. 50
• D. 25

Answer 1

The correct option is C 50

$10\text{mL}$ of $1MNaCl$ = $10\text{milli moles}$ of $NaCl$

According to the question,
$200\text{mL}$ of $A{s}_2{S}_3$ requires $10\text{millimoles}$ of $NaCl$ for coagulation.

$\therefore 1000\text{mL}$ of $A{s}_2{S}_3$ requires $=10\times \frac{1000}{200}\text{millimoles}$
$=50\text{millimoles}$ of $NaCl$ for coagulation.