Which is not a property of a pure substance? uniform composition varying composition fixed composition

Option (b) is the correct answer.

Explanation:

A pure substance is defined as a substance that consists of fixed composition of atoms.

For example, NaCl is a pure substance as it contains same composition of sodium and chlorine atoms.

Whereas a substance which has varying composition of atoms is known as a mixture. For example, mixture of sand in water.

Thus, we can conclude that varying composition is not a property of a pure substance.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.

answer carbon and three oxygen atoms;