A test for complete removal of ions from a solution of is to add

CHEMISTRY · Subjective · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry

Problem

A test for complete removal of

\text{Cu}^{2+}

ions from a solution of

\text{Cu}^{2+}(\text{aq.})

is to add

\text{NH}_3(\text{aq.})

. A blue colour signifies the formation of complex

[\text{Cu}(\text{NH}_3)_4]^{2+}

having

K_f = 1.1 \times 10^{13}

and thus confirms the presence of

\text{Cu}^{2+}

in solution. 250 mL of 0.1 M

\text{CuSO}_4(\text{aq.})

is electrolysed by passing a current of 3.512 ampere for 1368 second. After passage of this charge sufficient quantity of

\text{NH}_3(\text{aq.})

is added to electrolysed solution maintaining

[\text{NH}_3] = 0.10 \text{ M}

. If

[\text{Cu}(\text{NH}_3)_4]^{2+}

is detectable upto its concentration as low as

1 \times 10^{-5}

, would a blue colour be shown by the electrolysed solution on addition of

\text{NH}_3