An acid -base indicator has a Ka of 3.0 xx 10^(-5)The acid form of the indicator is red and the basic formis blue. Then

An acid -base indicator has a Ka of 3.0 xx 10^(-5)The acid form of the

1.	An acid -base indicator has a Ka of 3.0 xx 10^(-5)The acid form of the indicator is red and the basic formis blue. Then
Answer» pH is 4.05 whenindicator is 75 % RED pH is 5.00 when indicator is 75% blue pH is 5.00 when indicator is 75 % red pH is 4.05 when indicator is 75%blue SOLUTION :` K_a =([H^(+) ][In^(-)])/( [HIn]) ` ` if 75%red RARR ([HI_n])/([In^(-)])=(75)/(25) =3 ` ` rArr [H^(+) ] =3 XX 10 ^(-5)xx 3 ` ` pH =5- log 9 =4.05` ` if 75% blue rArr ([In^(-)])/([HI_n])= 3 ` ` [H^(+) ] = 10 ^(-5)rArr pH =5`