0.5mmol of NaCN and 1mmol of HCl in 1 L solution is a buffer.A. TrueB. False

B. False

A buffer is a solution that resists changes in pH when an acid or base is added to it. To act as a buffer, a solution typically requires a weak acid and its conjugate base or a weak base and its conjugate acid.

In this case, you have NaCN (sodium cyanide) and HCl (hydrochloric acid) in the solution. NaCN is the salt of a weak acid (hydrocyanic acid, HCN), but HCl is a strong acid. A buffer solution typically consists of a weak acid and its conjugate base or a weak base and its conjugate acid. Mixing a strong acid (HCl) with a salt of a weak acid (NaCN) does not create a proper buffer system. Therefore, the given solution is not a buffer.

Additionally, the relative concentrations of the components are also important for a solution to function as a buffer. Buffer capacity depends on the ratio of the concentrations of the weak acid and its conjugate base. The given concentrations of NaCN and HCl are not in the appropriate ratio for a buffer solution.