An acid base indicator `(K_(a) =10^(-5))` has its pH range 4.4 - 6.0. The correct statement (s) amongst the following is/are

Options

A. The indicator will be suitable for the titration of a strong acid against a weak base.
B. The acidic colour of the indicator wil predominate if the concentration of acidic form is 4 times more than that of the basic form.
C. The indicator will be suitable for the titration of weak acid against a strong base.
D. The basic colour of the indicator will prevail when concentration of basic form will be at least 10 times more than that of the acidic form.

Answer

A, B, D

Explanation

pH range ` lt 7 rArr ` good for weak base
(b) Acid colour dominate if pH ` lt 4.4 `
` i.e. pK_(In) +log ""( In^(-))/(HIn) lt 4.4 `
`rArr log ""(In^(-))/(HIn) lt 4.4 -5=-0.6`
( c ) basic colour will dominate if ` pH gt 6`
` rArr PK _(In) +log ""(I_n^(-) ) /(HIn) gt 6`
`rArr log ""( I_n^(-))/( HIn) gt 6-5=1 rArr (I_n^(-))/(HIn) gt 10 `