Question

1. How does carbon attain noble gas configuration ? 2. Draw electron dot structure of water molecule. 3. Write the name and formula of 2nd member of homologous series having general formula CnH2n. 4. Name the first member of ketones. 5. What is glacial acetic acid ? 6. Why carbon is tetravalent ? 7. An organic compound burns with blue clear flame. Is it saturated or unsatu- rated compound ? 8. Write the molecular formula of ethanol. 9. Which of the following will show addition reaction : C4H10, C2H6, C2H4, CH4, C3H8 ? 10. Name the gas evolved when ethanoic acid is added to sodium carbonate ? 11. Write balanced chemical equation of dehydration of ethanol by hot conc. H2SO4. 12. Name organic acid present in vinegar. 13. What is catenation ? 14. Why soap is not suitable for washing cloth when water is hard ? 15. How

Answer 1

1. Carbon attains noble gas configuration by forming covalent bonds.

2. Refer attachment.

3. $C_{n}H_{2n}$ ; n=2

Therefore the element is Ethylene with formula

$C_{2}H_{4}$

4. The first ember of ketone is 2-propanone, also known as Acetone.

5. Glacial acetic acid is acetic acid which contains less than 1% water.

6. Carbon has 4 valence electrons and needs 4 electrons to attain nearest noble gas configuration. Hence carbon is tetravalent.

7. Saturated compounds burns with blue clear flame as the single bond is easily breakable during combustion unlike unsaturated compounds which has double and triple bonds.

8. Molecular formula of Ethanol

$CH_{3}CH_{2}OH$   or   $C_{2}H_{5}OH$

9. Addition reaction happens in alkenes and alkynes. Of the given options the only unsaturated compound is

$C_{2}H_{4}$

10. Carbon dioxide is evolved during the reaction of ethanoic acid with sodium carbonate.

11.

$CH_{3}CH_{2}OH ----Con. H_{2}SO_{4}------> CH_{2}=CH_{2} + H_{2}O$

12. Acetic acid

13. Catenation is linkage of atoms of the same element into longer chains.

14. Hard water contains calcium and magnesium ions. When soap is used it forms calcium and magnesium salts and  forms scum. Hence, soap is not suitable for washing cloth when water is hard.

Answer 2

1. There are 4 electrons in the outer shell of carbon.

2. To attain noble gas configuration, it should either lose 4 or gain 4 electrons.

3. Propene is the compound that has a formula C3H6.

4. the first member is Propanone, the formula is C3H6O

5. It is somehting which has less than 1% of water and is also called water-free acid.