Question

(a) Name two metals which occur in nature in free state as well as in combined state.
(b) Name one ore of manganese. Which compound of manganese is present in this ore ? Also write its chemical formula.
(c) A zinc ore on heating in air forms sulphur dioxide. Describe briefly any two stages involved in the conversion of this concentrated ore into zinc metal.

Lakhmir Singh Chemistry Class 10

Answer 1

Answer:

(a)Copper and silver are the two metals that occur in free state as well as in combined state.

(b)compound manganese dioxide

Discovery and naming

One of the main ores of manganese is pyrolusite. Pyrolusite is made up primarily of the compound manganese dioxide (MnO 2 ).

(c)Roasting: When zinc sulphide (zinc blende ore) is strongly heated in air (roasted), it forms zinc oxide and sulphur dioxide.

Answer 2

Answers:

(a) Silver (Ag), Gold (Au), Platinum (Pt)

(b) Ore name : Pyrolusite

It contains manganese dioxide.

Chemical formula : MnO₂

(c) The zinc ore on heating in air forms sulphur dioxide is ZnS (Zinc Sulphide).

The proceed involves in the conversion of this ore into zinc is roasting.

Steps :

(i) 2ZnS + 3O₂ → 2ZnO + 2SO₂

(ii) ZnO + C → Zn + CO