Class 10 Science Chapter 4 MCQ for 2020-2021
| Class: 10 | Science |
| Chapter: 4 | Multiple Choice Questions (MCQ) Tests |
Class 10 Science Chapter 4 MCQ with Answers
Class 10 Science Chapter 4 MCQ Online tests practice with answers and explanation. Practice here to prepare your school test and board papers. Questions are taken form NCERT Books and answers are also confined to NCERT textbooks only.
Q1
Badal appeared in class test but he confused to know the correct statement. Would you help him to know that?
[A]. If we burn diamond in oxygen, then only carbon dioxide gas is formed and nothing is left behind.
[B]. Diamond does not conduct electricity.
[C]. Diamond and graphite are the two common allotropes of carbon which are known to us for centuries.
[D]. All the above.
Answer: Option D
Explanation:Here, all these statements are correct. Hence, your answer will be option [D].
Q2
Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g. hydrogen. After the formation of four bonds, carbon attains the electronic configuration of
[A]. Helium
[B]. Neon
[C]. Argon
[D]. Krypton
Answer: Option B
Explanation:Electronic configuration of carbon (C) = 2, 4 when it forms four covalent bonds by sharing its four valence electrons with hydrogen, it forms CH4 molecule.
You can easily understand by this:
Electronic configuration of C in CH4 = 2, 8.
Atomic number of Ne is 10. Its electronic configuration is (K2), (L8). Therefore, after the formation of four bonds carbon attains the electronic configuration of neon.
Q3
Badal appeared in class test but he confused to know the correct statement. Would you help him to know that?
[A]. Buckminsterfullerene is a dark solid at room temperature.
[B]. Buckminsterfullerene is an allotrope of carbon containing clusters of 60 carbon atoms joined together to form spherical molecules.
[C]. There are twenty hexagons and twelve pentagons of carbon atoms in one molecule of buckminsterfullerene.
[D]. All the above..
Answer: Option D
Explanation:Here, all these statements are correct. Hence, your answer will be option [D].
Q4
In the last year board examination, Rahul were asked a question where he had to choose the statement which was/were incorrect? Will you be able to answer this question?
[A]. A compound made up of hydrogen and carbon only is called hydrocarbon.
[B]. The property of carbon element due to which its atoms can join with one another to form long carbon chains is called “carbonization”.
[C]. The study of carbon compounds (such as hydrocarbons and their derivatives) is called organic chemistry
[D]. None of the above.
Answer: Option B
Explanation:The property of carbon element due to which its atoms can join with one another to form long carbon chains is called catenation. So, it is the property of “catenation” of carbon element which is responsible for a very large number of organic compounds (catenation means “self-linking”).
Q5
Which of the following statement is or are incorrect?
[A]. The general formula of alkynes is CH2n +2 where n is the number of carbon atoms in one molecule of the alkyne.
[B]. The unsaturated hydrocarbons are obtained mostly from petroleum by a process called cracking.
[C]. An unsaturated hydrocarbon in which the two carbon atoms are connected by a double bond is called an alkene.
[D]. The simplest alkene is ethene having the molecular formula C2H4.
Answer: Option A
Explanation:The general formula of alkynes is CnH2n – 2 where n is the number of carbon atoms in one molecule of the alkyne.
You can easily understand by this example:
Example, If an alkyne has 3 carbon atoms in its molecule, then n = 3, and its molecular formula will be C3H2×3–2 or C3H4.
Q6
In which of the following compounds, — OH is the functional group?
[A]. Butanone
[B]. Butanol
[C]. Butanoic acid
[D]. Butanal
Answer: Option B
Explanation:Butanol, CH3 – CH2 – CH2 – CH2 – OH.
The alcohols are organic compounds. They all contain the functional group –OH. This group possess the properties of alcohols. The names of alcohols end with -ol – e.g., ethanol, butanol.
Q7
Consider the following statements and choose the correct one:
[A]. The group formed by the removal of one hydrogen atom from an alkane molecule is called an alkyl group.
[B]. An unsaturated hydrocarbon in which the two carbon atoms are connected by a triple bond is called an alkyne.
[C]. An unsaturated hydrocarbon in which the two carbon atoms are connected by a double bond is called an alkene.
[D]. All the above.
Answer: Option D
Explanation:Here, all the statements are correct. Hence, your answer will be option [D].
Q8
A molecule of ammonia (NH3) has
[A]. Only single bonds
[B]. Only double bonds
[C]. Only triple bonds
[D]. Two double bonds and one single bond
Answer: Option A
Explanation:A molecule of ammonia (NH3) has only single bonds and these are covalent bonds.
Note: Atomic number of N is 7.
Its electronic configuration is 2, 5 so it needs 3 more electrons to complete its “Octet”. It gains 3 electrons each from 3 hydrogen atoms. Also, N has one lone pair of electrons.
The pair of electrons on the nitrogen atom in NH3 molecule which is not involved in bond formation is called lone pair.
Q9
In a science quiz competition, Priyanka are asked a question where she had to choose the statement which was/were incorrect?
[A]. The IUPAC name of the compound CH3COCH2CH2CH3 is pentanone.
[B]. The IUPAC name of the compound CH3COCH2CH3 is butanone.
[C]. The IUPAC name of CH3COCH3 is propanone
[D]. The common name of pentanone is ethyl methyl ketone.
Answer: Option D
Explanation:The common name of pentanone is methyl propyl ketone.
Q10
Consider the following statements and choose the incorrect one:
[A]. The simplest ketone is acetone, CH3COCH3, which is also known as propanone.
[B]. The common name of propanal (CH3CH2CHO) is propionaldehyde.
[C]. Ethanal (CH3CHO) contains 2 carbon atoms, so its parent hydrocarbon is ethane.
[D]. None of the above.
Answer: Option D
Explanation:Here, all these statements are correct. Hence, your answer will be option [D].
Why does Carbon not form an ionic bonds?
There are two main reasons for not forming an ionic bonds.
- It could gain four electrons forming C4– anion. But it would be difficult for the nucleus with six protons to hold on to ten electrons, that is, four extra electrons.
- It could lose four electrons forming C4+ cation. But it would require a large amount of energy to remove four electrons leaving behind a carbon cation with six protons in its nucleus holding on to just two
electrons.
Why are covalent compounds poor conductors of electricity?
Covalent compounds are formed by the sharing of electrons. Since the electrons are shared between atoms and no charged particles are formed, such covalent compounds are generally poor conductors of electricity.
What is meant by catenation?
The unique ability to form bonds combining one atom with other atoms of carbon, giving rise to large molecules is called catenation.
What is Glacial acid?
The melting point of pure ethanoic acid is 290 K and hence it often freezes during winter in cold climates. This gave rise to its name glacial acetic acid.
What are isomers?
Compounds with identical molecular formula but different structures
are called structural isomers.
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