Which may be added to one litre of water to act a buffer?

Options

A. One mole of `HC_(2)H_(3)O_(2)` and one mole of HCI
B. One mole of `NH_(4)OH` and one mole of NaOH
C. One mole of `NH_(4)CI` and mole of HCI
D. One mole of `HC_(2)H_(3)O_(2)` and `0.5` mole of NaOH

Answer

D

Explanation

`{:(HC_(2)H_(3)O_(2)+,NaOHrarr,C_(2)H_(3)O_(2)Na+,H_(2)O),(1,0.5,0,0),(0.5,0,0.5,0.5):}`
This solution contains, `underset(0.5 Mol e)("weak acid")+underset(0.5 Mol e)("its salt")` and thus acts as buffer.