Calculate the molar ratio of a weak acid ( H A (K_a=10⁻⁶ ) ) and its salt with strong base, so that the ( pH ) of buffer solution is 6 .

Step-by-step solution

( aligned & pH = pK + [ Salt ] [ Acid ] [ Salt ] [ Acid ] & = pH p K_a = 6 6 =1 & [K_a=10⁻⁶ p K_a=- K_a= (10⁻⁶ ) 6 ] & [ Salt ] [ Acid ] =1 & [ Acid ] [ Salt ] =10⁻¹ or 0.1 aligned ) Hence, the correct option is (d).