HORT ANSWER TYPE QUESTIONS (2 Marks)
1. What are hydrocarbons ? Give examples.
2. Why does carbon atom forms a large number of compounds ?
3. Write down two characteristics of the compounds of an homologous series.
4. Covalent compounds generally don't conduct electricity. Why?
5. Write down structural formula of:
(a) Propanone
(b) Hexanal
6. Why carbon is unique in nature ?
55
Science Class - 10
Answers
Answer:
1) Compounds of carbon and hydrogen are called hydrocarbons. For example, methane, ethane, etc. Saturated hydrocarbons contain carbon-carbon single bonds.
2) Carbon is the only element that can form so many different compounds because each carbon atom can form four chemical bonds to other atoms, and because the carbon atom is just the right, small size to fit in comfortably as parts of very large molecules.
3) Features include a general formula and neighbouring members differing by CH2, with similar chemical properties and with a gradation in physical properties. Homologous series are 'families' of organic compounds. They share common characteristics: They all contain the same functional group.
4) Covalent compounds do not conduct electricity because they are formed between non metal atoms by sharing of electrons. Covalent compounds have no free electrons and no ions and hence they do not conduct electricity.
5) Acetone, or propanone, is the organic compound with the formula (CH3)2CO.
Hexanal C6H12O
6) Carbon is the only element that can form so many different compounds because each carbon atom can form four chemical bonds to other atoms, and because the carbon atom is just the right, small size to fit in comfortably as parts of very large molecules.