Complete the missing components/variables given as a and y in the following reactions: (i) Pb(NO3)2(aq) + 2KI(aq) β PbI2(x) + 2KNO3(y) (ii) Cu(s) + 2AgNO3(aq) β Cu(NO3)2(aq) + x(s) (iii) Zn(s) + H2SO4(ag) β ZnSO4(x) + H2(y) (iv) πͺππͺπΆπ(π) β π πͺππΆ(π) + πͺπΆπ(π)