Question

Question No. 2
Mg + 2 HCl → MgCl2 + H2
The ratio of Mg (at. mass = 24) used to H2 produced by weight is:
Options
O 1:12
O 12:1
O 24 : 1
O 1:6​

Answer 1

Solution:- (C) 30

As we know that,

No. of moles=  

mol. wt.

wt.

​  

 

Now,

Wt. of Mg=6g

Mol. wt. of Mg=24g

No. of moles of Mg in 6g=  

24

6

​  

=0.25 moles

Mg+H  

2

​  

SO  

4

​  

⟶MgSO  

4

​  

+H  

2

​  

 

from the above reaction,

1 mole of magnesium sulphate is formed when 1 mole of magnesium reacts.

Therefore,

0.25 mole of magnesium sulphate is formed when 0.25 mole of magnesium reacts.

Now,

Mol. wt. of MgSO  

4

​  

=120g

Therefore,

Wt. of 0.25 moles of MgSO  

4

​  

=0.25×120=30g

Hence 30g of magnesium sulphate is formd when 6g of magnesium reacts with excess of H  

2

​  

SO  

4

​  

.