Question

In the average composition of portland cement, the percentage of magnesium oxide is a ___________

(a) 3 to 4%

(b) 2 to 3%

(c) 4 to 5%

(d) 1 to 2%

I got this question during an online exam.

This is a very interesting question from s-Block Elements topic in division s-Block Elements of Chemistry – Class 11

Answer 1

Correct choice is (b) 2 to 3%

To elaborate: Cement is an important building material. The average composition of portland cement is calcium oxide of 50 to 60%, Silicon dioxide of 20 to 25%, aluminium oxide of 5 to 10%, magnesium oxide of 2 to 3%, ferric oxide of 1 to 2% and sulphur trioxide of 1 to 2%.