'Metals are usually not found as nitrates in their ores'
Out of the following two (a and b) reasons which isare/are true for the above observation?
I. Metal nitrates are highly unstable.
II.Metal nitrates are highly soluble in water.

• I and II are true

• I and II are false

• I is false but II is true

• I is false but II is true

Roasting of sulphides gives the gas X as a by-product. This is a colourless gas with the choking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic acts as a reducing agent and its acid has never been isolated. The gas X is

• H₂S

• SO₂

• CO₂

• CO₂

Aluminium is extracted from alumina (Al₂O₃) by electrolysis of a molten mixture of 

• Al₂O₃ +HF +NaAlF₄

• Al₂O₃ + CaF₂ +NaAlF₄

• Al₂O₃ +Na₃AlF₆ +CaF₂

• Al₂O₃ +KF +Na₃AlF₆

Which one of the following is a mineral of iron?

• Malachite

• Cassiterite

• Pyrolusite

• Magnetite

155.

In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with

• Copper (I) sulphide (Cu₂S)

• sulphur dioxide (SO₂)

• Iron sulphide (FeS)

• Iron sulphide (FeS)

Identify the alloy containing a non-metal as a constituent in it.

• Invar

• Steel

• Bell metal

• Bell metal

Which of the following elements is present as the impurity to the maximum extent in the big iron?

• Carbon

• Silicon

• Phosphorus

• Phosphorus

Which of the following pairs of metals is purified by van Arkel method?

• Zr and Ti

• Ag and Au

• Ni and Fe

• Ni and Fe

In the extraction of copper from its sulphide ore, the metal finally obtained by the reduction of cuprous oxide with 

• Iron (II) sulphide

• Carbon monoxide

• Copper (I) sulphide

• Copper (I) sulphide

Which of the following statements in incorrect?

• pure sodium metal dissolves in liquid ammonia to give blue solution

• NaOH reacts with glass to give sodium silicate

• Aluminium reacts with excess NaOH to give Al(OH)₃

• Aluminium reacts with excess NaOH to give Al(OH)₃