Equilibrium Question 425
Question: Given that the dissociation constant for $ H_2O $ is $ K_{w}=1\times {10^{-14}} $
$ mole^{2}litr{e^{-2}}, $ what is the $ HCl $ of a $ 0.001molarKOH $ solution [MP PET 1995; MP PET/PMT 1998]
Options:
A) $ {10^{-11}} $
B) 3
C) 14
D) 11
Show Answer
Answer:
Correct Answer: D
Solution:
0.001 M KOH solution $ [O{H^{-}}]=0.001,M=1\times {10^{-3}}M $
$ [{H^{+}}]\times [O{H^{-}}]=1\times {10^{-14}} $
$ [{H^{+}}]=\frac{1\times {10^{-14}}}{[O{H^{-}}]} $
$ [{H^{+}}]=\frac{1\times {10^{-14}}}{1\times {10^{-3}}} $
$ =1\times {10^{-14}}\times {10^{+3}} $
$ [{H^{+}}]={10^{-11}} $ M $ pH=11 $
