istinguish between ionic and molecular compounds in terms of the basic
units that each is composed of.

In molecular compound atoms are held together through covalent bond. It is formed between the non metals.

In ionic compounds positive and negative ions held together through electrostatic attraction. It is formed between metal and non metal.

Explanation:

Ionic compound:

In ionic compounds positive and negative ions held together through electrostatic attraction. It is formed between metal and non metal.

For example:

Sodium chloride is ionic compound. Te sodium metal lose it electron and this electron is accept by the chlorine atom. Sodium became positive ion while chlorine became negative ion. The forces develop between them are electrostatic forces.

Molecular compound:

In molecular compound atoms are held together through covalent bond. It is formed between the non metals.

For example:

Carbon dioxide is molecular compound. It is made up of carbon and oxygen atoms. Both atoms share the electrons with each other and form two double bond O=C=O.

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.