Additin of sodium hydroxide solution to a weak acid (HA)results in a buffer of pH 6. If ionition constant of HA is 10^$$-$$5, the ratio of salt to acid concentration in the buffer solution will be :

Excess of NaOH (aq) was added to 100 mL of FeCl₃ (aq) resulting into 2.14 g of Fe(OH)₃ . The molarity of FeCl₃ (aq) is :

(Given molar mass of Fe = 56 g mol⁻¹ and molar mass of Cl = 35.5 g mol₋₁)

What is the standard reduction potential (E^o) for Fe³⁺ $$ \to $$ Fe ?
Given that :
Fe²⁺ + 2e^$$-$$ $$ \to $$ Fe; $$E_{F{e^{2 + }}/Fe}^o$$ = $$-$$0.47 V
Fe³⁺ + e^$$-$$ $$ \to $$ Fe²⁺; $$E_{F{e^{3 + }}/F{e^{2 + }}}^o$$ = +0.77 V

A mixture containing the following four compounds is extracted with $$1M$$ $$HCl.$$ The compound that goes to aqueous layer is :