2:31 know that acids in aqueous solution are a source of hydrogen ions and alkalis in a aqueous solution are a source of hydroxide ions

An acid is source of hydrogen ions (H⁺).

An alkali is source of hydroxide ions (OH^–).

Spec	Q'stion	Ans	MS
2:31	Jan '14 (1), Q 8 c iii	Answer	MkS
2:31	Jan '15 (1), Q 5 c i	Answer	MkS
2:31	Jan '16 (1), Q 11 b ii	Answer	MkS
2:31	Jan '18 (1), Q 7 c i	Answer	MkS
2:31	May '10 (2), Q 6 a i	Answer	MkS
2:31	May '10 (2), Q 6 a ii	Answer	MkS
2:31	May '14 (1), Q 8 c ii	Answer	MkS
2:31	May '16 (1), Q 7 a ii	Answer	MkS
2:31	May '16 (1R), Q 6 e	Answer	MkS
2:31	May '16 (2R), Q 5 c ii	Answer	MkS