Copper II Sulphate

Q. When $CuS{O}_4$ is treated with excess KCN solution, what compound(s) is/are formed?

1. $K\left[Cu\right(CN{)}_2]$
2. $K_3\left[Cu\right(CN{)}_4]$
3. $K_2\left[Cu\right(CN{)}_4]$
4. $N\equiv C-C\equiv N$

Q. covalent bonds arevstrong and directional in nature. what does this statement mean

Q. Which of the following statements is wrong about $CuS{O}_4$?

1. It reacts with $KI$ to give $I_2$
2. It reacts with $KCl$ to give $C{l}_2$
3. Its tartarate complex reacts with $NaOH$ and glucose which on heating gives $C{u}_{2}O$
4. It gives $CuO$ on strong heating in the presensce of air