Question

11] The molecular weight of an unknown substance is found to 24000. If it contains 0.2%
Magnesium, then the number of Magnesium atoms that can be present in a molecule of it is.
a) 1
b)2
d) 10
c) 4​

Answer 1

Molecular weight of the substance= 24000g

Molar Mass of Mg = 24g

percentage of Mg in that= 0.2%

Amount of Mg = % of Mg*Molecular weight of substance/100

= 0.2*24000/100

=48g of mg is present

No of Mg atoms= Amount of Mg/Molar Mass of Mg

= 48/24

= 2 atoms

Ans = Option C