What is the number of electrons lost by a metal atom to form a positive ion called?

Write the balanced chemical equation for the reaction of aluminium when heated in air. Also,write the name of the product.

When a metal $X$ is treated with cold water, it gives a basic salt $Y$ with molecular formula $XOH$ (molecular mass $= 40$) and liberates a gas $Z$ which easily catches fire. Identify $X$, $Y$, and $Z$, and write the chemical reaction involved.

Which of the following metals are obtained by electrolysis of their molten chlorides?
$(i) Na, (ii) Ca, (iii) Fe, (iv) Cu$

In a blast furnace,what prevents the oxidation of molten iron?

Why is hydrogen gas not evolved when a metal reacts with nitric acid?