Question

How does the pH of a solution of manganese hydroxide , Mn ( OH )2 dissolved in a 0 . 10 M Mn ( NO3 ) 2 compare to the pH of the Mn ( OH )2 dissolved in Water ?

A-The pH of the solution of Mn ( OH )2 dissolved in an aqueous solution of Mn ( NO3 )2 is lower (more acidic ) than Mn(OH )2 dissolved in water.

B-The pH of the solution of Mn ( OH )2 dissolved in an aqueous solution of Mn ( NO3 )2 is unaffected.

C-The pH of the solution of Mn ( OH )2 dissolved in an aqueous solution of Mn ( NO3 )2 is neutral.

Answer 1

pH related problem:

How does the pH of a solution of manganese hydroxide , Mn ( OH )2 dissolved in a 0 . 10 M Mn ( NO3 ) 2 compare to the pH of the Mn ( OH )2 dissolved in Water ?

A) Mn(OH)2 <-----> Mn⁺² + 2 OH^-

   Mn(NO3)2 ------> Mn⁺² + 2 NO₃^-

Due to common ion effect concentration of OH- ions decreases and consequently pH of solution decreases, that means acidicty increases (more acidic) than that of Mn(OH)2 dissolved in water.

B) pH of Mn(OH)2 dissolved in aqueous solution of Mn ( NO3 )2 is affected.

C) The pH of the solution of Mn ( OH )2 dissolved in an aqueous solution of Mn ( NO3 )2 is not neutral. Due to common ion effect, pH of solution is decreases than that of the Mn(OH)2 in aqueous solution.