Carbon and its Compounds — Science STD 10 — Question

Using electron-dot diagrams which show only the outermost shell electrons, show how a molecule of nitrogen, N, is formed from two nitrogen atoms. What name is given to this type of bonding? (Atomic number of nitrogen is 7)

A metal ‘X’ loses two electrons and a non-metal ‘Y’ gains one electron. Show the electron dot structure of compound formed between them. Is it ionic or covalent? Does it have high melting point or low? Will it conduct electricity in solid state or in aqueous solution and why? Will it be soluble in water?

Name two properties of elements whose magnitudes change when going from top to bottom in a group of the periodic table. In what manner do they change?

The metal salt A is blue in colour. When salt A is heated strongly over a burner, then a substance B is eliminated and a white powder C is left behind. When a few drops of a liquid D are added to powder C, it becomes blue again. What could be A, B, C and D?

Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?

What are esters? How are esters prepared? Write the chemical equation for the reaction involved. What happens when an ester reacts with sodium hydroxide? Write the chemical equation for the reaction and also state the name and use of this reaction.

A hard material X which is mined from the earth is used as a house hold fuel and also for the generation of electricity at Thermal Power Stations. A soft material Y is also used us a fuel in the form of candles. A gaseous material Z which occurs along with petroleum is increasingly being used as a fuel in running vehicles in its compressed form.

1. What are materials, X, Y and Z?
2. When materials X, Y and Z are burned separately:

1. When material burns by producing a yellow, luminous flame?
2. Which material ultimately burns without producing a flame?
3. Which material can burn in a gas stove by producing a blue flame?

Draw the electron dot structure of ethyne and also draw its structural formula.

How does the method used for extracting a metal from its ore depend on the metal’s position in the reactivity series? Explain with examples.

When a green iron salt is heated strongly, its colour finally changes to brown and odour of burning sulphur is given out:

1. Name the iron salt.
2. Name the type of reaction that takes place during the heating of iron salt.
3. Write a chemical equation for the reaction involved.