A) 7
B) slightly less than 7
C) slightly greater than 7
D) 1
Correct Answer: B
Solution :
\[[{{H}^{+}}]\] ions from \[HCl\] acid\[=1\times {{10}^{-7}}M\] Here, \[[{{H}^{+}}]\] ions from\[{{H}_{2}}O={{10}^{-7}}M\]cannot be neglected in comparison to \[{{10}^{-7}}M[{{H}^{+}}]\] ions from\[HCl\]. \[\therefore \]Total\[[{{H}^{+}}]={{10}^{-7}}+{{10}^{-7}}\] \[={{10}^{-7}}(1+1)\] \[=2\times {{10}^{-7}}M\] \[pH=-\log [{{H}^{+}}]\] \[=-\log [2\times {{10}^{-7}}]\] \[=-[\log 2+\log {{10}^{-7}}]\] \[=-(0.3010-7)\] \[=6.6989\] \[\therefore \]\[pH\] of a solution of \[1\times {{10}^{-7}}M\] is slightly less than 7.
You need to login to perform this action.
You will be redirected in
3 sec
