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5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Seven

Conjugate acid of a weak base is always stronger. What will be the decreasing order of basic strength of the following conjugate bases?

OH– , RO– , CH3COO– , Cl–
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V
Vishal Baghel

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: Conjugate acid of a weak base is always stronger and conjugate base of weak acid is always strong.

The weak acids are:

⇒H2O, ROH, CH3COOH, HCl

⇒HCl > CH3COOH > ROH > H2O

⇒ Conjugate base order ⇒ OH−>RO−>CH3COO−>Cl−

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

How can production of hydrogen from water gas be increased by using water gas shift reaction?
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P
Payal Gupta

Contributor-Level 10

This is a short answer type question as classified in NCERT Exemplar

Water-gas shift reaction: The water-gas shift reaction is a chemical reaction in which carbon monoxide reacts with steam in the presence of a catalyst to form carbon dioxide and hydrogen.

CO+H2+H2O → CO2+2H2

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Seven

Ionisation constant of a weak base MOH, is given by the expression

kb= [ M + ] [ O H - ] [ M O H ]

Values of ionisation constant of some weak bases at a particular temperature are given below:

                        Base

                        K b

Dimethylamine

5.4 * 10–4

Urea

1.3 * 10–14

Pyridine

1.77 * 10–9

Ammonia

1.77 * 10–5

Arrange the bases in decreasing order of the extent of their ionisation at equilibrium. Which of the above base is the strongest?
0 Follower 1 View

V
Vishal Baghel

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: Higher the value of Kb stronger will be the base. 

Kb-  5.4 * 10-4 >1.77 * 10-5 > 1.77 * 10-9> 1.3 * 10-14

Decreasing order of basic strength. 

Dimethylamine > Ammonia > Pyridine > Urea

Hence among the given bases, the strongest base is Dimethylamine. 

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

Sodium forms a crystalline ionic solid with Dihydrogen. The solid is non-volatile and non-conducting in nature. It reacts violently with water to produce Dihydrogen gas. Write the formula of this compound and its reaction with water. What will happen on electrolysis of the melt of this solid?
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P
Payal Gupta

Contributor-Level 10

This is a long answer type question as classified in NCERT Exemplar

Sodium reacts with Dihydrogen to form sodium hydride which is a crystalline ionic solid.

2Na + H2 → 2Na + H-

It reacts with H2O to produce H2 gas

2NaH+2H2O → 2NaOH+2H2

Although Na+H- does not conduct electricity in the solid state, the electrolysis of its melt produces H2 at the anode and Na at the cathode.

                                      At cathode  At anode

Na + H- (l) → &nbs

...more

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Seven

BF3 does not have proton but still acts as an acid and reacts with NH3. Why is it so? What type of bond is formed between the two?
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V
Vishal Baghel

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: BF3 does not have a proton but still it acts as a Lewis acid as it is an electron pair acceptor and reacts with NH3by accepting its lone pair of electrons. The reaction can be represented by Coordinate bond is formed between BF3 and NH3. It can be represented as-

  [ BF3 ← :NH3]

Nitrogen acts as lone pair donator in this combination

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Seven

The aqueous solution of sugar does not conduct electricity. However, when sodium chloride is added to water, it conducts electricity. How will you explain this statement on the basis of ionisation and how is it affected by concentration of sodium chloride?
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V
Vishal Baghel

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: Conductance of a solution depends upon the number of ions present in the solution since sodium chloride is an ionic compound when mixed in water it ionizes completely forming an aqueous electrolytic solution. Hence, the solution conducts electricity while sugar being a non-electrolyte does not ionize in water and when concentration of NaCl is increased, more Na+ and Cl-  ions will be produced. Hence, conductance increases.

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Seven

The ionisation of hydrochloric in water is given below:

HCl(aq) + H2O (l ) ⇌ H3O+ (aq) + Cl– (aq)

Label two conjugate acid-base pairs in this ionization.
0 Follower 4 Views

V
Vishal Baghel

Contributor-Level 10

This is a Short Answer Type Questions as classified in NCERT Exemplar

Ans: Conjugate acid and conjugate base can be shown as-

HCl(aq) + H2O (l) ? H3O+(aq) + Cl-(aq) 

 acid        base        conjugate    conjugate

                             acid          base

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

An ionic hydride of an alkali metal has significant covalent character and is almost unreactive towards oxygen and chlorine. This is used in the synthesis of other useful hydrides. Write the formula of this hydride. Write its reaction with Al2Cl6.
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Payal Gupta

Contributor-Level 10

This is a long answer type question as classified in NCERT Exemplar

It is lithium hydride (LiH) because it has significant covalent character due to the smallest alkali metal, LiH is very stable. It is almost nonreactive towards oxygen and chlorine. It reacts with Al2Cl2 to form lithium aluminium hydride.

8LiH+ Al2Cl6 → 2LiAlH4 → LiCl

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Seven

Write a relation between ∆G and Q and define the meaning of each term and answer the following :

(a) Why a reaction proceeds forward when Q < K and no net reaction occurs when Q = K.

(b) Explain the effect of increase in pressure in terms of reaction quotient Q. for the reaction :

 CO (g) + 3H2 (g) ⇌ CH4 (g) + H2O (g)
0 Follower 5 Views

V
Vishal Baghel

Contributor-Level 10

This is a Long Answer Type Questions as classified in NCERT Exemplar

Ans: (a) As we know, 

ΔG=  ?G? +RTlnQ

?G? = Change in free energy as the reaction proceeds,

ΔG = Standard free energy change,

Q = Reaction quotient,

R = Gas constant,

T = Absolute temperature.

Since,  ?G? =−RTlnK

∴ΔG=−RTlnK + RTlnQ = RTlnKQ?

If Q

If Q=K, ΔG=0, reaction is in equilibrium and no net reaction is there.

 

(b) When we increase the pressure equilibrium will shift in forward direction it means Q

Types of Chemical Reactions :

There are 4 main types of chemical reactions. These are-

  1. Combination
...more

New answer posted

5 months ago

Class 11th Chemistry NCERT Exemplar Solutions Class 11th Chapter Nine

A colourless liquid 'A' contains H and O elements only. It decomposes slowly on exposure to light. It is stabilised by mixing urea to store in the presence of light.

(i) Suggest possible structure of A.
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P
Payal Gupta

Contributor-Level 10

This is a long answer type question as classified in NCERT Exemplar

Since, a colourless liquid 'A' contains only hydrogen and oxygen and decomposes slowly on exposure to light but is stabilised by addition of urea, therefore, liquid A may be hydrogen peroxide. A is H2O2. 

Structure of H2O2 is given below.

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