11.4 Alkynes — Chemistry STD 10 — Question

Give the names of the first four members of the homologous series of
alkynes.

Define :
a covalent compound.

Carbon shows some unique properties, name them ?

What do you understand by an alkali? Give two examples of:
(a) strong alkalis
(b) weak alkalis

(a) Why do elements form ions in certain chemical reactions?
(b) What kind of elements form positively charged ions? Support your answer by two examples.

Explain the following:
A solution of cane sugar does not conduct electricity, but a solution of solution of sodium chloride is a good conductor.

Give reason for the following:
When concentrated sulphuric acid is exposed to air, its volume increases and it becomes slightly dilute.

state two properties of brass that render it more useful for some purpose than its components?

Explain the following :
zinc is used to cover iron so as to prevent rusting of iron. why?