Nouns - some confusion (iron vs rod)


I have confusion while identifying the nouns.

  1. I purchased one iron rod.
    iron - Material Noun.
    rod - Common Noun.

  2. Jaipur is the capital of Rajasthan.
    Jaipur - Proper Noun.
    Capital - Common Noun.
    Rajasthan - Proper Noun.

  3. A herd of elephants destroyed the village.
    herd- Collective Noun.
    elephant - Common Noun.
    village - Common Noun.

  4. Gold is a precious metal.
    Gold - Material Noun.
    Metal - Common Noun.

Am I correct?
Pl. help me.

Debasish Joardar.

Looks fine to me. Where did you take these exercises from, are they part of a homework assignment?[YSaerTTEW443543]

TOEIC short conversations: Requisition request[YSaerTTEW443543]