Answer
a) $MgSO_{4}$
b) $Na_{2}SO_{4}$
c) $NiSO_{4}$
d) $Al_{2}(SO_{4})_{3}$
e) $Li_{2}SO_{4}$
Work Step by Step
a) valency of Mg = 2 and $SO_{4}$ is also 2. So, the formula is $MgSO_{4}$
b) valency of Na = 1 and $SO_{4}$ is 2. So, the formula is $Na_{2}SO_{4}$
c) valency of Ni = 2 and $SO_{4}$ is also 2. So, the formula is $NiSO_{4}$
d) valency of Al = 3and $SO_{4}$ is 2. So, the formula is $Al_{2}(SO_{4})_{3}$
e) valency of Li =1 and $SO_{4}$ is 2. So, the formula is $Li_{2}SO_{4}$
