# 10 ml of a solution contains 0.1M NH4Cl + 0.01M  NH4OH. Which addition would not change the PH of the solution?  Option 1) Adding 1ml water  Option 2) Adding 5ml of 0.1M NH4Cl Option 3) Adding 5ml of 0.1M NH4OH Option 4) Adding 10ml of 0.1NH4Cl

As we discussed in concept

Buffer Solutions -

The solutions which resist change in pH on dilution or with addition of small amounts of acid or alkali are called buffer solution.

- wherein

Many body fluids  e.g.  blood

pOH of a buffer solution = $pK_b\:+\:log\frac{[salt]}{base}$

pH = 14 - pOH

Adding 1ml of water would not affecr the concentration of salt or base as much as to make a change in pH of the solution. That is not the case with other options.

Option 1)

This option is correct.

Option 2)

This option is incorrect.

Option 3)