Question

The equilibrium $2Cu \rightleftharpoons C{u^0} + C{u^{2 + }}$ in aqueous medium at ${25^ \circ }C$ shift towards the left in presence of:
This question has multiple correct options
$A.$ $NO_3^ - $
$B.$ $C{l^ - }$
$C.$ $SC{N^ - }$
$D.$ $C{N^ - }$

Answer 1

Hint:We can tell whether a reaction shift towards left or right it is depend on the given reaction $C{u^ + }$ oxidize to $C{u^{2 + }}$ if a reducing agent is present which reduce $C{u^{2 + }}$ to $C{u^ + }$ it shift the given reaction to the left.

Complete step-by-step answer:$2Cu \rightleftharpoons C{u^0} + C{u^{2 + }}$ in aqueous medium at ${25^ \circ }C$ shift towards the left in presence of a reducing agent because reducing agent reduce $C{u^{2 + }}$ to $C{u^ + }$ . Out of $NO_3^ - $ , $C{l^ - }$ , $SC{N^ - }$ and $CN_{}^ - $ only $C{l^ - }$ , $SC{N^ - }$ and $C{N^ - }$ are reducing agent. They have a tendency to lose and hence, reduce $C{u^{2 + }}$ to $C{u^ + }$ thus shifting the reaction towards the left.

Additional information:
$NO_3^ - $ : $NO_3^ - $ is a polyatomic ion. Salt containing $NO_3^ - $ anion is called nitrates. Nitrates are a common component of explosives and fertilizers. Generally, the Nitrates are soluble in water but insoluble in non-polar solvent such as Benzene due to its polar nature. A common examples of an inorganic nitrate salt is sodium nitrates
$C{l^ - }$ : $C{l^ - }$ is the negative charged anion. Salt containing $C{l^ - }$ anions is called chloride. A most common example of an inorganic salt Sodium chloride, generally chlorides are soluble in water or other polar solvent.
$SC{N^ - }$ : $SC{N^ - }$ is a polyatomic ion. It is called Thiocyanate, it is a pseudohalide anion obtained by deprotonation of the thiol groups of thiocyanic acid. Organic compounds containing the functional group $SCN$ are also called thiocyanate.
$C{N^ - }$ : A $C{N^ - }$ is a polyatomic ion. In $C{N^ - }$ Carbon and nitrogen consist of three bonds between them, Salt containing $C{N^ - }$ anion is known as cyanide. A most common example is potassium cyanide and sodium cyanide.

So, the correct option is $B,C$ and $D.$

Note: A reducing agent is a constituent such as ion, atoms and molecules which reduce other species and oxidize itself losing electrons whereas a oxidizing agent is a constituent which oxidizes others and reduces itself by gaining electrons.