Solutions of Carbon And Its Compounds (Page No - 243) - Chemistry Lakhmir Singh, Class 10 | Extra Documents, Videos & Tests for Class 10 PDF Download

Question 56:
An organic compound having the molecular formula C₂H₆0 can exist in the form of two isomers A and B having different functional groups. The isomer A is a liquid which is used as a solvent for nail polish. The isomer B is also a liquid. An aqueous solution of one of the lower homologues of B is used for preserving biological specimens in the laboratory
 (a) What is compound A ?
 (b) Write the electron-dot structure of A.
 (c) What is compound B ?
 (d) Write the electron-dot structure of B.
 (e) Name the lower homologue of compound B which is used in preserving biological specimens.
 Solution :

(a) Propanone (or Acetone)

(c) Propanal

(e) Methanal (or Formaldehyde) is used in preserving biological specimens.

Question 57:
A hard material X which is mined from the earth is used as a household fuel and also for the generation of electricity at Thermal Power Stations. A soft material Y is also used as 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.
 (a) What are materials, X, Y and Z ?
 (b) When materials X, Y and Z are burned separately :
 (i) Which material burns by producing a yellow, luminous flame ?
 (ii) Which material ultimately burns without producing a flame ?
 (iii) Which material can burn in a gas stove by producing a blue flame ?
 Solution :
(a) X is coal; Y is wax; Z is natural gas
(b)(i) Y (wax)
(ii) X (coal)
(iii) Z (natural gas)

Question 58:
Three organic compounds A, B and C have the following molecular formulae :
 A C₄H₈O₂
 B C₄H₁₀O
 C C₄H₈O
 (a) Which compound contains an alcohol group ? Write its name and structural formula.
 (b) Which compound contains a carboxyl group ? Write its name and structural formula.
 (c) Which molecular formula can represent an aldehyde as well as a ketone ? Write the names and structural formulae of the aldehyde and ketone represented by this molecular formula.
Solution :

Question 59:

A colourless organic liquid X of molecular formula C₂H₄0₂ turns blue litmus to red. Another colourless organic liquid Y of molecular formula C₂H₆0 has no action on any litmus but it is used as a nail polish remover. A yet another colourless organic liquid Z of molecular formula C₂H₆O has also no action on litmus but it is used in tincture of iodine.
 (a) Name the liquid X. To which homologous series does it belong ? Give the name of another member of this homologous series.
 (b) Name the liquid Y. To which homologous series does it belong ? Write the name of another member of this homologous series.
 (c) Can you name an organic compound having the same molecular formula as liquid Y but which belongs to a different homologous series ? What is this homologous series ?
 (d) Name the liquid Z. To which homologous series does it belong ? Write the name of another member of this homologous series.
 Solution :
(a) Liquid X is ethanoic acid; it belongs to homologous series of carboxylic acids. Methanoic acid is another member of this homologous series.
(b) Liquid Y is Propanone; it belongs to homologous series of ketones. Butanone is another member of this homologous series.
(c) Propanal; it belongs to homologous series of aldehydes.
(d) Liquid Z is ethanol; it belongs to homologous series of alcohols. Methanol is another member of this homologous series.

Question 60:
You are given an organic compound having the molecular formula C₂H₈. Give the name and formula of the compound formed :
 (a) when one H atom of C₃H₈ is replaced by a Cl atom.
 (b) when one H atom of C₃H₈ is replaced by OH group.
 (c) when one H atom of C₃H₈ is replaced by a CHO group.
 (d) when one H atom of C₃H₈ is replaced by a COOH group.
 (e) when two H atoms joined to the middle carbon atom of C₃H₈ are replaced by one O atom.
 Solution :
(a) Chloropropane, CH₃-CH₂-CH₂-Cl
(b) Propanol, CH₃-CH₂-CH₂-OH
(c) Butanal, CH₃-CH₂-CH₂-CHO
(d) Butanoic acid, CH₃-CH₂-CH₂-COOH
(e) Propanone, CH₃-CO-CH₃