During the neutralisation of an acid by a base, the end point refers to the completion of reaction. The detection of end point in acid-base neutralisation is usually made by an acid-base indicator. An acid-base indicator is itself a weak acid (Phenolphthalein) or a weak base (Methyl orange). At `50%` ionisation which depends on the medium. the anion furnished by an indicator (acid) cation furnished colour to solution at end point. For example, phenolphthalein dissociation
`underset("Colourless")(HIn)toH^(+)+underset("Pink")(In^(-)),K_(HIn)=([H^(+)][In^(-)])/([HIn])`
is favoured in presence of alkali and pink colour of phenolphthalein ion is noticed as soon as the medium changes to alkali nature. The end point of acid-base neutralisation not necessarily coincides with eqivalence point but it is closer to equivalence point. Also at equivalence point of acid-base neutralisation, pH is not necessarily equal to 7.
Which among the followig statements are correct?
(P) At equivalence point of NaOH AND HCI,pH=7
(Q) At equivalence point of NaOH and `CH_(3)COOH,pH gt 7`
(R) At equivalence point of `NH_(4)OH` and `HCI,pH lt 7`
(S) An indicator shows best results if equivalence point is within the pH range `pK_(In)pm1`
(T) ) At equivalence point of `NH_(4)OH` and formic acid `pH lt 7`

Options

A. P,Q,R,S and T
B. P,R,S and T
C. P,S and T
D. P,Q,R and T

Answer

a