Which of the following have a pH less than seven.
The property which is not shown by acids is :
(a) they have a sour taste
(b) they feel soapy
(c) they turn litmus red
(d) their pH is less than seven
Give one example each of a salt which gives an aqueous solution having :
(a) pH less than 7
(b) pH equal to 7
(c) pH more than 7