Ionic Equilibrium Question 6
Question 6 - 29 January - Shift 1
Millimoles of calcium hydroxyide required to produce $100 mL$ of the aqueous solution of $pH 12$ is $x \times 10^{-1}$. The value of $x$ is (Nearest integer).
Assume complete dissociation.
Show Answer
Answer: (5)
Solution:
Formula: Calculation of pH and no. of moles
$\because pH=12$
$\therefore[H^{+}]=10^{-12} M$
$\therefore[OH^{-}]=10^{-2} M$
$\therefore[Ca(OH)_2]=5 \times 10^{-3} M$
$5 \times 10^{-3}=\frac{\text{ milli moles of } Ca(OH)_2}{100 mL}$
milli moles of $Ca(OH)_2=5 \times 10^{-1}$
Ans. $=5$
