✓ Board-verified
Science · 2023 · 5 marks
CBSE 2023 · Region 6 · Set 2 · Q34
(a) (i) What are isomers? Write the structures of two compounds having molecular formula C_3 H_6 O and give their names. (ii) What are soaps? How are…
(i)
What are isomers ? Write the structures of two compounds having molecular formula $\displaystyle \mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}$ and give their names.
(ii)
What are soaps ? How are they chemically different from detergents ? Why do soaps not work effectively in hard water ?
(i)
What is a homologous series of carbon compounds ? Write general formula for alkynes. Name and draw the electron dot structure of first homologue of this series.
(ii)
State the meaning of the functional group in an organic compound. Write the formula of the functional group present in alcohols and carboxylic acids.
Marking-scheme solution
(i)
Compounds having same molecular formula but different structural
formula
Structures are :
Propanal
Propanone
(ii)
-Soaps are sodium or potassium salts of long-chain carboxylic acids /
$\displaystyle \mathrm{R}-\mathrm{COO}^{-} \mathrm{Na}^{+}$
detergents are ammonium salts with chlorides or bromides ions or
Sodium salts of sulphonic acids/ $\displaystyle \mathrm{R}-\mathrm{OSO}_{3}{ }^{-} \mathrm{Na}^{+}$
Soaps react with calcium or magnesium ions present in hard water to
form an insoluble substance / soaps react with hard water forming scum.
(i)
A series of compounds in which the same functional group substitutes
for hydrogen in a carbon chain / having similar chemical. properties and
differ by $\displaystyle -\mathrm{CH}_{2}$.
General formula $\displaystyle \mathrm{C}_{\mathrm{n}} \mathrm{H}_{2 \mathrm{n}-2}$
Ethyne
Electronic dot structure
(ii)
Functional group is an atom or a group of atoms (hetero atom) bonded
to a carbon chain. It defines the chemical property of the organic
compound.
Alcohol - OH
Carboxylic Acid
All Metals and Non-metals questions2023 question paperNCERT solutions: Metals and Non-metalsPractice Metals and Non-metals →
More from Metals and Non-metals
- (i) It is observed that covalent compounds are bad conductors of electricity. Give reason. (ii) Carbon can neither form C^4+ cation nor C^4- anion.…2023
- A metal, M, displaces iron from aqueous solution of ferrous sulphate but fails to do so in case of aqueous solution of aluminium sulphate. The metal…2025
- Sodium metal is stored under kerosene oil. Why? Some metal oxides are soluble in water. What are the aqueous solutions of these oxides called? Write…2024
- List two advantages of adopting the atomic number of an element as the basis of classification of elements in the Modern Periodic Table. Write the…2022
- Consider the following organic compounds: (i) (ii) Name the functional group present in their compounds. Write the general formula for the compounds…2022
- Attempt either or: (i) Write one example each of one metal that is so soft that it can be cut with a knife, and one non-metal that is a good…2026
- Cinnabar is an ore of a metal 'X'. When this ore is heated in air, it is first converted into oxide of 'X' (XO) and then reduced to metal 'X' on…2025
- Which of the following is an alloy of copper and tin?2024
CBSE Class 10 Science past-paper question from the 2023 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.