Among the following, the correct statements is

Options

A. pH decreases when solid ammonium chloride is added toa a dilute aqueous soplution of `NH_(3)`
B. pH decreases when solid sodium acetate is added to a dilute aqueous solution of acetic acid.
C. pH decreases when solid NaCl is added to a dilute aqueous solution of NaOH
D. pH decreases when solid sodium oxalate is added to a dilute aqueous solution of oxalic acid

Answer

A

Explanation

Dil aqueous Solutionof `NH_(3)" is "NH_(4)OH` solution
`NH_(3)OHhArrNH_(4)^(+)+overset(-)OH`
On adding solid ammonium chloride
`NH_(4)rarrNH_(4)^(+)+Cl^(-)`
The reaction moves backward due to common ion effect. The concentration of `OH^(-)` decreases and pH decressess.