Carbon and its Compounds — Science STD 10 — Question

Lithium, sodium and potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements? Explain your answer.

How many structural isomers can you draw for pentane?

A student prepared solutions of (i) an acid and (ii) a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?

What happens when.

1. ZnCO₃ is heated in the absence of oxygen?
2. A mixture of Cu₂O and Cu₂S is heated?

How can diamonds be made artificially? How do synthetic diamonds differ from natural ones?

Catenation is the ability of an atom to form bonds with other atoms of the same element. It is exhibited by both carbon and silicon. Compare the ability of catenation of the two elements. Give reasons.

Which chemical is injected into the skin of a person:
During the nettle leaf hair sting?
How can the effect of these stings be neutralised?

Giving one example each, state what are (i) ionic compounds, and (ii) covalent compounds.

A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?