Chemistry

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This is a multiple choice answer as classified in NCERT Exemplar

Option (i) and (ii)

When an electron is removed from a hydrogen atom, the nucleus decreases to 1.5 * 10^-3 pm in size. When compared to usual atomic and ionic sizes of 50 to 200 pm, this is exceedingly small. As a result, H+ does not exist independently and is always bound to other atoms or molecules.

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How will you prepare the following compounds from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom

(i) Methyl benzoate

(ii) m-Nitrobenzoic acid

(iii) p-Nitrobenzoic acid

(iv) Phenylacetic acid

(v) p-Nitrobenzaldehyde.

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Chemistry Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

Contributor-Level 10

1. When benzene is treated with Br₂ In presence of ferric bromide (brominating agent) they form bromobenzene. When bromobenzene is treated with Mg in ether it will form Grignard reagent, and if the CO₂ is treated with Grignard reagent (in acidic condition) it will form benzoic acid. After esterification reaction in presence of methanol it will form methyl benzoate.

2. When benzene is treated with Br₂ In presence of ferric bromide (brominating agent) they form bromobenzene. When bromobenzene is treated with Mg in ether it will form Grignard reagent, and if the CO₂ is treated with Grignard reagent (in acidic condition) it will f

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Which of the following statement(s) is/are correct in the case of heavy water?

(i) Heavy water is used as a moderator in nuclear reactor.

(ii) Heavy water is more effective as solvent than ordinary water.

(iii) Heavy water is more associated than ordinary water.

(iv) Heavy water has lower boiling point than ordinary water.

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Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

Option (i) and (iii)

Heavy water is utilised as a moderator in nuclear reactors and exchange reactions, and it is more associated with water due to its higher mass.

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Give simple chemical tests to distinguish between the following pairs of compounds.

(i) Propanal and Propanone

(ii) Acetophenone and Benzophenone

(iii) Phenol and Benzoic acid

(iv) Benzoic acid and Ethyl benzoate

(v) Pentan-2-one and Pentan-3-one

(vi) Benzaldehyde and Acetophenone

(vii) Ethanal and Propanal

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Chemistry Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

Contributor-Level 10

a )Tollen's test –Due to oxidizing nature of aldehydes they get easily oxidized, wheareas in case of ketones they are not readily

oxidizable. And tollens test exploits this fact, [Ag (NH₃)₂]⁺ is used as reagent Ag mirror is formed during this reaction

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Dihydrogen can be prepared on a commercial scale by different methods. In its preparation by the action of steam on hydrocarbons, a mixture of CO and H₂gas is formed. It is known as

(i) Water gas

(ii) Syngas

(iii) Producer gas

(iv) Industrial gas

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Chemistry Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

Option (i) and (ii)

The combination of CO and H₂ is known as water gas. This mixture of CO and H₂is also known as synthesis gas or 'syngas' since it is used to make methanol and other hydrocarbons.

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9 months ago

In the following questions two or more options may be correct.

Which of the following statements are not true for hydrogen?

(i) It exists as a diatomic molecule.

(ii) It has one electron in the outermost shell.

(iii) It can lose an electron to form a cation which can freely exist.

(iv) It forms a large number of ionic compounds by losing an electron.

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Chemistry Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

Option (iii) and (iv)

H⁺ does not exist freely and is always associated with other atoms or molecules. It has an extremely high ionisation enthalpy and does not have metallic properties under normal conditions, unlike alkali metals.

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Only one element forms hydride.

(i) Group 6

(ii) Group 7

(iii) Group 8

(iv) Group 9

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Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

Option (i)

Group 6

From group 6, only chromium forms CrH.

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Arrange the following compounds in increasing order of their property as indicated:

(i) Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl tert-butyl ketone (reactivity towards HCN)

(ii) CH₃CH₂CH(Br)COOH, CH₃CH(Br)CH₂COOH, (CH₃)₂CHCOOH, CH₃CH₂CH₂COOH (acid strength)

(iii) Benzoic acid, 4-Nitrobenzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxybenzoic acid (acid strength)

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Chemistry Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

Contributor-Level 10

1. Di-tertbutyl, ketone

2. +I effect donates e^- . Br group will show +I effect along the chain but as I effect is distance dependent effect it will die as the distance increase.+I effect of alkyl group will reduce the acidity of a compound whereas –I effect will increase the acidity, I effects are distance dependent, correct order will be (CH₃)₂CHCOOH< CH₃CH₂CH₂COOH< CH₃CH (Br)CH₂COOH < CH₃CH₂CH (Br)COOH.

3. As we know the electron releasing groups (ERG) reduces the acidic strength of the compound (via inductive effect) whereas the electron withdrawing group (EWG) will increase the acidic strength of compound, and methoxy group is

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9 months ago

Elements of which of the following group(s) of periodic table do not form hydrides?

(i) Groups 7, 8, 9

(ii) Group 13

(iii) Groups 15, 16, 17

(iv) Group 14

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Contributor-Level 10

This is a multiple choice answer as classified in NCERT Exemplar

Option (i)

Groups 7,8, 9

Explanation: The metals belonging to group 7, 8 and 9 do not have tendency to form hydrides.

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An organic compound (A) (Molecular formula C₈H₁₆O₂) was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) And an alcohol (C). Oxidation of (C) with chromic acid produced (B). (C) On dehydration gives but-1-ene. Write equations for the reactions involved.(Intermediate)

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