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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
An element belonging to group 14 of the periodic table has two common allotrpoes A and B. A is very hard and a non conductor of electricity while B is soft to touch and good conductor of electricity . Identify the element . Name each of these allotropes. |
| Answer» The element of gorup 14 having two common allotropes is crabon . These two allotropes (A and B) of carbon element are diamond and graphite. This is confirmed by the fact that diamond is very hard and a non conductor of elelctricity whereas graphite is soft to touch and good conductor of electricity | |
| 102. |
Which of the following represents saponification reaction ?A. `CH_(3)COONa+NaOHoverset(CaO)toCH_(4)+Na_(2)CO_(3)`B. `CH_(3)COOH+C_(2)H_(5)OH overset(H_(2)SO_(4))toCH_(3)COOC_(2)H_(5)+H_(2)O`C. `2CH_(3)COOH+2Nato2CH_(3)COONa+H_(2)`D. `CH_(3)COOC_(2)H_(5)+NaOHtoCH_(3)COONa+C_(2)H_(5)OH` |
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Answer» Correct Answer - D This is an example of saponification reaction. All other options are not correct. |
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| 103. |
Why is candle flame generally yellow? |
| Answer» Candle flame is generally yellow due to the presence of unburnt carbon particles. When light falls on these particles, they scatter yellow colour. This shows that the combustion of hydrocarbons present in wax or candle is not complete. | |
| 104. |
Draw the electron dot structure of ethyne and also draw its structure of ethyne and also its structural formula. |
| Answer» `underset(("Electron dot structure"))(H:C::C:H)" "underset(("Structural formula"))(H-C-=C-H)` | |
| 105. |
Structural formula of ethyne isA. `HC-=CH`B. `H_(3)C-C-=CH`C. D. `HC=CH` |
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Answer» Correct Answer - A It is the correct answer. |
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| 106. |
Mention any three physical properties of graphite. |
| Answer» Very soft , metallic lustre, bad conductor of heat and good conductor of electricity . | |
| 107. |
In which of the following compounds -OH is the functional group ?A. ButanoneB. ButanolC. ButanoicD. Butanal |
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Answer» Correct Answer - B Butanol, `CH_(3)-CH_(2)-CH_(2)-CH_(2)-OH` The general formula of alcohols is `C_(n)H_(2n)+1-OH`. For butanol, n = 4 So, formula is `C_(4)H_(9)-OH or CH_(3)-CH_(2)-CH_(2)-CH_(2)-OH` |
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| 108. |
Why is the conversion of ethanol to ethanoic acid an oxidation reaction? |
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Answer» Ethanoic acid `(CH_(3)COOH)` has one oxygen ato more and two hydrogen atoms less than ethanol `(C_(2)H_(5)OH)`. In general * Loss of hydrogen is known as oxidation. * Gain of oxygen is known as oxidation. Therefore, it is an oxidation raction. |
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| 109. |
State two characteristic features of carbon which when put together give rise to a large number of carbon compounds. |
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Answer» (i) The size of carbon atom is very small (Atomic radius=77pm) (ii) The strength C-C bond is quite high (355 kJ `mol^(-1)`) therefore, any number of carbon atoms can be linked by covalent bonds. This self linking property is called catenation. |
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| 110. |
Would you be able to check if water is hard by using a detergent? |
| Answer» Detergent gives lather with hard and soft water both, while a soap gives lather with soft water only. Thus, it not possible to check if water is hard by using a detergent. | |
| 111. |
People use a variety of methods to wash clothes. Usually after adding the soap, they ‘beat’ the clothes on a stone, or beat it with a paddle, scrub with a brush or the mixture is agitated in a washing machine. Why is agitation necessary to get clean clothes? |
| Answer» The purpose of soap or detergent in washing is to reduce friction between oil drops carrying dirt particles and water so that they may mix with each other. All the methods that have been suggested loosen the bonds between the dust or oil particles and fabrics of clothes. the agitation helps ini washing the clothes. | |
| 112. |
How will you convert ethane into ethanol? Give the chemical reaction involved. |
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Answer» Ethene is converted into ethanol by passing its vapours through water in the presence of sulphuric acid. This reaction is called hydration of ethane. `H_(2)C=CH_(2)+H_(2)Ooverset((H_(2)SO_(4)))toCH_(3)-CH_(2)-OH` |
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| 113. |
Ethane, with the molecular formula `C_(2)H_(6)` hasA. 6 covalent bonds.B. 7 covalent bonds.C. 8 covalent bonds.D. 9 covalent bonds. |
| Answer» (b) 7 covalent bonds. | |
| 114. |
What is meant by allotropy ? |
| Answer» Different physical forms, almost similar chemical properties. | |
| 115. |
One of the following is notan allotrope of carbon . This is :A. diamondB. graphiteC. cumeneD. buckninistrefullerene |
| Answer» Correct Answer - C | |
| 116. |
Write full form of CFC. |
| Answer» Chlorofluorocarbons. | |
| 117. |
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 ofA. heliumB. neonC. argonD. krypton |
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Answer» Correct Answer - B The compound formed is methane `(CH_(4))`. In this carbon atom has a complete octet and configuration of neon which is a noble gas element. |
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| 118. |
How would you bring about the following conversions ? Name the process and write the reaction involved. (a) Ethanol to ethene , (b) Propanol to propanoic acid Write the reactions. |
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Answer» (a) `underset("Ethanol")(CH_(3)CH_(2)OH)underset(160^(@)-170^(@)C)overset("Conc."H_(2)SO_(4))toCH_(2)=CH_(2)+H_(2)O` The name of the reaction dehydration. (b) `underset("Propanol")(CH_(3)CH_(2)CH_(2)-)underset("heat")overset("Alk".KMnO_(4))tounderset("Propanoic acid")(CH_(3)CH_(2)COOH)` The name of the reaction is oxidation reaction. |
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| 119. |
Look at the figure and answer the following questions. (a) What change would you observe in the calcium hydroxide solution taken in tube B ? (b) Write the reaction involved in test tubes A and B respectively. (c ) If ethanol is given instead of ethanoic acid, would you expect same change ? (d) How can a solution of lime water be prepared in the laboratory ? |
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Answer» (a) When `CO_(2)` is passed through calcium hydroxide solution (taken in test tube B), i.e., lime water, it turns milky due to the formation of insoluble calcium carbonate `(CaCO_(3))`. (b) Test tube A `underset("Sodium carbonate")(Na_(2)CO_(3))+underset("Ethanoic acid")(CH_(3)COOH)+underset("Carbon dioxide")(CO_(2))+H_(2)O` (c) If ethanol taken instead of ethanoic acid, no change will because ethanol is a very weak acid and hence cannot decompose `Na_(2)CO_(3)` to give `CO_(2)` gas. `underset("Ethanol")(CH_(3)CH_(2)OH)+N_(2)CO_(3)to"No reaction"` (d) When quick lime (CaO) is added to water in a test tube. Some of it will dissolve to from calcium hydroxide (lime water) while majority of it remains suspended. Filter the solution. The clear solution thus obtained is called lime water. `underset("Quick lime")(CaO(s))+H_(2)O(l)to"Suspension"overset("Filter")tounderset("Lime water")(Ca(OH)_(2)).(aq)` |
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| 120. |
Which element exhibits the property of catenation to maximum and why? |
| Answer» The element is carbon. This is because of very samll size of carbon atom (77 pm) and high strength of C-C bond (355 kJ `mol^(-1)`) | |
| 121. |
The pair of elements which exhibits the properity of catenation is :A. Sodium and siliconB. chlorine and carbonC. carbon and sodiumD. silicon and carbon |
| Answer» Correct Answer - A::D | |
| 122. |
Account for the following statements: (i) Ethene is a covalent compound. (ii) Carbon atoms from a strong bond. (iii) Carbon shows catenation property. (iv) Pentane has higher boiling point than methane. (v) Alkenes have double bonds. |
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Answer» (i). (ii). (iii). (iv). Boiling point temperature pentane (309K) is higher than that of methane because its molecular size is more. As a result, inter-molecular forces of attraction in pentane are more than in ethane. (v). |
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| 123. |
Catenation is the ability of an atom to form bonds with other atoms of the same element . It is exhibited by both carbon and silicon. Compare the ability of catenation of the two elements .Give reasons. |
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Answer» Both carbon (C ) and silicon (Si) have similar valence shell electronic configuration i.e., each has four electrons in the valence shell hence show the phenomenon of catenation. But carbon exhibits catenation much more than silicon or nay other element due to its smaller size which makes the C-C bonds strong while the Si-Si bonds are comparatively weaker due to its large size. Thus, due to greater strength of C-C over Si-Si bonds, carbon shows catenation to a greater extent than silicon. |
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| 124. |
The chemical which is not required for the preparation of soap in the laboratory is :A. vegetable oilB. baking sodaC. caustic sodaD. common salt |
| Answer» Correct Answer - (b) | |
| 125. |
Compounds that give a brisk effervescence with sodium hydrogen carbonate areA. ethanolB. vegetable oilC. vinegarD. soap solution |
| Answer» Correct Answer - (c ) | |
| 126. |
How will you name the following compounds? (a) `CH_(3)-overset(H)overset(|)(C)=O ` (b) `CH_(3)-CH_(2)-OH` (c). `H-overset(H)overset(|)(C)=O` (d) `CH_(3)-CH_(2)=Cl`. |
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Answer» (a) Ethanal (b) Ethanol (c) Methanal (d) Chloroethane. |
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| 127. |
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties ? |
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Answer» (a) Differences in physical properties: (i) Smell: Ethanol has a pleasant smell whereas ethaoci has a pungent smell (like that of vinegar). (ii) Taste. Ethanol has a burning taste whereas ethanoci acid has a sour taste. (iii) Boiling points: The boiling point of ethanol is low (being only `78^(@)C` ) whereas that of ethanoic acid is comparatively high (being `118^(@)C`). (b) Differences in chemical properties: (i) Action on litmus: Ehtanol has no action on any litmus (so it is a neutral compound) but ethanoic acid turns blue litmus to red (so it is an acidic compound). (ii) Action on sodium hydrogencarbon. Ethanol has no reaction with sodium hydrogencarbonate but ethanoic acid gives brisk effervescence of carbon dioxide with sodium hydrogencarbonate. |
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| 128. |
The molecular formulae of some organic compounds are given below .Which of these compounds contains an aldehyde group?A. `C_(6)H_(8)O`B. `C_(3)H_(6)O_(2)`C. `C_(3)H_(6)O`D. `C_(3)H_(7)CI` |
| Answer» Correct Answer - (c ) | |
| 129. |
One of the following molecular formulae represents a ketone .This formula is :A. `C_(5)H_(12)O`B. `C_(6)H_(12)O_(2)`C. `C_(6)H_(14)O`D. `C_(6)H_(12)O` |
| Answer» Correct Answer - (d) Ketone group, -CO- | |
| 130. |
An aldehye as well as a ketone can be represented by the same molecular formula, say `C_(3)H_(6)O`. Write their structures and name them. State the relation between the two in the language of science. |
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Answer» `underset("Propan")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-overset(O)overset(||)(C)-H)" "underset("Propanone")(H-underset(H)underset(|)overset(H)overset(|)(C)-overset(O)overset(||)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H)` These two compounds are related to each other as functional isomers. |
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| 131. |
Starting from the hydrocarbon butane, write the structures and IUPAC names of (i) Chloroderivative(ii) alcohol (iii) aldehyde (iv) carboxylic acid (v) amine (vi) ketone. |
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Answer» The molecular formula of butane is `C_(4)H_(10)` and its structural formula is `CH_(3)-CH_(2)-CH_(2)-CH_(3)`. (i) `underset("1-Chlorobutane")(overset(4)(C)H_(3)-overset(3)(C)H_(2)-overset(2)(C)H_(2)-overset(1)(C)H_(2)-Cl)` (ii) `underset("Butane-1-ol")(overset(4)(C)H_(3)-overset(3)(C)H_(2)-overset(2)(C)H_(2)-overset(1)(C)H_(2)-OH)` (iii) `underset("Butanal")(overset(4)(C)H_(3)-overset(3)(C)H_(2)-overset(2)(C)H_(2)-overset(1)(C)HO)` (iv) `underset("Butanoic acid")(overset(4)(C)H_(3)-overset(3)(C)H_(2)-overset(2)(C)H_(2)-overset(O)overset(||)(.^(1)(C))-OH)` (v) `underset("Butane-1-amine")(overset(4)(C)H_(3)-overset(3)(C)H_(2)-overset(2)(C)H_(2)-overset(1)(C)H_(2)-NH_(2))` (vi) `underset("Butanone")(CH_(3)-overset(O)overset(||)(C)-CH_(2)-CH_(3))` |
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| 132. |
Give the names of the following: (i) An aldehyde derived from methane. (ii) ketone derived from butane (iii) The compound obtained by the oxidatino of ethanol with chroic anhydride. |
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Answer» (i) methanal (HCHO) (ii) Butanone `(CH_(3)COCH_(2)CH_(3))` (iii) Ethanal `(CH_(3)CHO)` |
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| 133. |
Chlorine reacts with saturated hydrocarbons at room temperature in theA. absence fo sunlightB. presence of sunlightC. absence of moistureD. presence of `H_(2)SO_(4)` |
| Answer» Correct Answer - (b) | |
| 134. |
Chlorine reacts with saturated hydrocarbons at room temperature in theA. absence of sunlightB. Presence of sunlightC. presence of waterD. presence of hydrochloric acid |
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Answer» Correct Answer - B Chlorine reacts with saturated hydrocarbon at room temperature in the presence of sunlight. `underset("Hydrocarbon")(R-H)+underset("Chlorine")(Cl_(2))overset(hv)toR-Cl+HCl(-"R si any alkyl group i.e.,"-CH_(3),-C_(2)H_(5),"etc".)` |
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| 135. |
The first member of alkyne homologous series isA. ethyneB. etheneC. propyneD. methane |
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Answer» Correct Answer - A The general formula of alkyne `C_(n)H_(2n-2)` where, n is the number of carbon atoms. The first member of alkyne homologous series is ethyne `C_(2)H_(2)`. |
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| 136. |
When ethnol is heated with alkaline potassium permanganate solution it gets converted in to ethanoic acid.In this rection , alkaline potassium permanganate acts as:A. reducing agentB. oxidising agentC. catalystD. dehydrating agent |
| Answer» Correct Answer - (b) | |