Question

What are the reaction products for the hydrolysis of the cyanide ion: CN° + H20 ? product 1: product 2: What is the buffer capacity (in mol/L) if 12.8 mL of 0.107 M NaOH is required to change the pH of 10.0 mL of buffer from 5.80 to 6.80? Hint: * mol/L

Answer 1

1. Ans :-

The complete balance chemical reaction is :

CN- + H2O ----------------> HCN + OH-

So,

Product 1 : HCN and

Product 2 : OH^-

This is acid-base reaction which gives the conjugate acid (HCN) of base CN^- and conjugate base (OH^-) of acid H₂O.

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2. Ans :-

Buffer capacity = Number of acid or base added / (Change in pH)x (Volume of buffer in L) ...............(1)

As,

Number of moles = Molarity of solution x Volume of solution in L

So,

Number of moles of NaOH added = 0.107 M x 0.0128 L

= 0.0013696 mol

Change in pH = 6.80 - 5.80 = 1.0

Given Volume of buffer = 10.0 mL = 0.010 L

Now, Put these values in equation (1) :

Buffer capacity = 0.0013696 / 1.0 x 0.010 L

= 0.13696 mol/L

= 0.137 mol/L

Hence, Buffer capacity of solution = 0.137 mol/L