Metals and Non-metals Test - 1

Explanation:

Pyrolusite is a mineral consisting essentially of manganese dioxide (MnO₂). It is an important ore of manganese. It is a black, amorphous mineral, often with a granular, fibrous or columnar structure.

Explanation:

Platinum (Pt), Gold (Au) and Silver (Ag) occur in their free or native state.

Explanation:

This reaction is an example of thermite process (also known as the Goldschmidt process). When aluminum powder reacts with iron oxide, a large amount of heat is released and a temperature of about 3500°C is attained which is enough to weld broken metallic parts.

Explanation:

Chemical reduction is used for enrichment of oxide ores. Hydraulic washing, Magnetic separation and Froth floatation method are used for the concentration of an ore. Hydraulic washing is based on the differences in gravities of the ore and the gangue particles. Froth floatation process is a process employed for the concentration or enrichment of a sulphide ore.

Explanation:

Solder is a fusible metal alloy used to join metals for electrical work. Soldering differs from welding in that soldering does not involve melting the work pieces.

Explanation:

Hydrated copper sulphate (CuSO₄) is blue in colour. When water is then added to anhydrous copper sulphate, it turns into the pentahydrate form, acquiring a blue color, and is commonly known as blue vitriol.

Explanation:

Galvanisation is the process of applying a protective coating of zinc to iron to prevent the rusting of iron. The most common method is hot dip galvanizing, in which steel sections are submerged in a bath of molten zinc.

Explanation:

The Iron pillar at Delhi was manufactured by the forge welding of pieces of wrought iron.

Explanation:

Most metals are sonorous i.e. they produce a deep and ringing sound when hit.

Explanation:

The melting point of NaCl is 801 ^oC or 1074 K