Solveeit Logo

Question

Chemistry Question on Acids and Bases

The pHpH of a 10810^{-8} molar solution of HClHCl in water is

A

88

B

between 77 and 88

C

between 66 and 77

D

None of these

Answer

between 66 and 77

Explanation

Solution

pH=log[H+]=log108=8pH =-\log \left[ H ^{+}\right]=-\log 10^{-8}=8

It is not possible for acid, so it is [H+],\left[ H ^{+}\right], the [H+]\left[ H ^{+}\right] of water is also added. Total [H+]\left[ H ^{+}\right] in solution

=[H+]=\left[ H ^{+}\right] of HCl+[H+]HCl +\left[ H ^{+}\right] of water

=(1×108+1×107)M=\left(1 \times 10^{-8}+1 \times 10^{-7}\right) M

=(1+10)×108=11×108M=(1+10) \times 10^{-8}=11 \times 10^{-8} M

pH=log[H+]\therefore pH =-\log \left[ H ^{+}\right]

=log11×108=-\log 11 \times 10^{-8}

=log11+8log10=-\log 11+8 \log 10

=1.0414+8=6.9586=-1.0414+8=6.9586