What is the ratio of dihydrogen gas to dinitrogen gas used in the production of ammonia gas by Haber's process?

Generally, metals react with acids to produce salt and hydrogen gas. Which of the following acids does not produce hydrogen gas when reacting with most metals (except $Mn$ and $Mg$)?

An alloy has a low melting point and is,therefore,used for electrical fuses. Name the alloy and write its constituents.

Which metal is purified by the method of liquation?

Which furnace is used to extract iron metal from its ore?

Give reasons for the following:
$(a)$ School bells are made of metals.
$(b)$ Electrical wires are made of copper.