Question

in the molecular formula of ALCL2 write the valency of aluminium and chlorine

Answer 1

molecular formula of aluminum chloride is AlCl3

since , we cross multiply the valency of both elements ,we get

valency of aluminum is +3
valency of chloride is 1- (it is a negative ion)

Al Cl
+3 -1

when , we cross multiply , Al1Cl3
which can also be written as AlCl3

l = L

hope this helps

Answer 2

you did mistake ,
molecular formula of aluminum chloride is AlCl₃.
here,
we know,
oxidation number of chlorine = -1, hence valancy of chlorine = 1
So, oxidation number of Al : x + 3(-1) = 0
⇒x - 3 = 0
⇒x = +3
Hence , oxidation number of Al = +3
Hence, valancy of Al = 3

or , if you say about molecular formula of AlCl₂⁺
Then, oxidation number of Al : x +2(-1) = 1
⇒x -2 = 1
⇒x = +3
Hence , in both cases oxidation number of Al = +3, so valancy of Al = 3