Question

Which of the following elements would form oxides which would indicate pH values less than seven, using moist pH paper ?

Magnesium, Carbon, Sulphur, Hydrogen, Copper

Answer 1

Metal oxides are basic in nature and non-metal oxides are acidic in nature. Magnesium and copper are metals and form basic oxides. Carbon, sulphur and hydrogen are non-metals and form acidic oxides. Hence, oxides of copper, sulphur and hydrogen will show a pH less than seven.