Tags Ncert Solutions Chemistry Class 12th

Ncert Solutions Chemistry Class 12th

Get insights from 2.6k questions on Ncert Solutions Chemistry Class 12th, answered by students, alumni, and experts. You may also ask and answer any question you like about Ncert Solutions Chemistry Class 12th

Follow Ask Question

2.6k

Questions

Discussions

Active Users

Followers

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemical Kinetics

A graph of volume of hydrogen released vs time for the reaction between zinc and dil. HCl is given in Fig. 4.2. Based on this mark the correct option

(I) Average rate upto 40s is $\frac{V_{3} - V_{2}}{40}$

(II) Average rate upto 40 seconds is $\frac{V_{3} - V_{2}}{40 - 30}$

(III) Average rate upto 40 seconds is $\frac{V_{3}}{40}$

(IV) Average rate upto 40 seconds is $\frac{V_{3} - V_{1}}{40 - 20}$

0 Follower 6 Views

alok kumar singh

Contributor-Level 10

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option C

In the given graph V is the volume in the Y axis and time is in X axis

Zn + dil.HCl→ZnCl₂ + H₂↑

Average rate = 40s

Average rate of reaction = $\frac{C h a n g e i n C o n c e n t r a t i o n o f H_{2}}{C h a n g e i n t i m e}$

$\frac{F i n a l C o n c e n t r a t i o n - I n i t i a l C o n c e n t r a t i o n}{F i n a l t i m e - I n i t i a l T i m e}$

Analyzing the graph line where time and volume intersect.

$\frac{V_{3} - 0}{40 - 0}$

$\frac{V_{3}}{40}$

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemical Kinetics

Consider the Arrhenius equation given below and mark the correct option.

k = Ae

A. Rate constant increases exponentially with increasing activation energy and decreasing temperature.

B. Rate constant decreases exponentially with increasing activation energy and decreasing temperature.

C. Rate constant increases exponentially with decreasing activation energy and decreasing temperature.

D. Rate constant increases exponentially with decreasing activation energy and increasing temperature.

0 Follower 2 Views

alok kumar singh

Contributor-Level 10

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option D

k = Ae - $\frac{E a}{R T}$

From this equation

Kα $\frac{1}{E a}$

When Activation energy Ea decreases, rate constant k

increases.

Hence, Rate constant increases exponentially with decreasing activation energy and increasing temperature.

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemical Kinetics

According to Arrhenius equation rate constant k is equal to A^e - . Which of the following options represents the graph of in k vs .

0 Follower 11 Views

alok kumar singh

Contributor-Level 10

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option A

Arrhenius equation Ae - $\frac{E a}{R T}$

K = rate constant

A= frequency factor

Ea= Activation Energy

R= gas constant

T= temperature

ln k = lnA - $\frac{E a}{R T}$

When the temperature rises, ln falls.

∴ ln kv/s $\frac{1}{T}$ , is a negative slope.

ln A is intercepted by k, and its magnitude decreases with time.

∴ Negative slope is obtained.

When compared to the other possibilities, T is increasing over time, which is incorrect.

ln k = $\frac{- E a}{R}$ $\frac{1}{T}$ + lnA

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemical Kinetics

Consider a first order gas phase decomposition reaction given below:

A(g) → B(g) + C(g)

The initial pressure of the system before decomposition of A waspt . After lapse of time 't', total pressure of the system increased by x units and became 't' the rate constant k for the reaction is given as _________.

0 Follower 10 Views

alok kumar singh

Contributor-Level 10

This is a Fill in the blanks Type Question as classified in NCERT Exemplar

Ans: Correct option B

Given:

A (g) → B (g) + C (g)

p_i= Initial pressure

(Time) t = 0

A (g) → B (g) + C (g)

p_i→0atm + 0atm

t, (p_i - x)atm

p_t = (p_i - x)atm + x + x = p_i + x

p_A = (p_i- x)

The value of x changes when it is substituted.

p_A = p_i- (p_t - p_i) = 2p_i- p_t

K = $\frac{2.303}{t}$ log $\frac{p_{i}}{2 p_{i} - p_{t}}$

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Ten

Assertion- Nitration of chlorobenzene leads to the formation of m-nitrochlorobenzene

Reason :−NO₂ group is a m-directing group.

(i) Assertion and reason both are correct and reason is correct explanation of assertion.

(ii) Assertion and reason both are wrong statements.

(iii) Assertion is correct but reason is wrong statement.

(iv) Assertion is wrong but reason is correct statement.

(v) Assertion and reason both are correct statements but reason is not correct explanation of assertion.

0 Follower 3 Views

Payal Gupta

Contributor-Level 10

This is a assertion and reason answer type question as classified in NCERT Exemplar

Because m-nitrochlorobenzene is not a stable molecule, the -NO₂ group is a meta-directing group, and the reactions' products include nitro groups at the o- and p- positions.

Correct Answer: Option (iv)

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Ten

Assertion : Hydrolysis of (−)−2-bromooctane proceeds with inversion of configuration.

Reason : This reaction proceeds through the formation of a carbocation.

(i) Assertion and reason both are correct and reason is correct explanation of assertion.

(ii) Assertion and reason both are wrong statements.

(iii) Assertion is correct but reason is wrong statement.

(iv) Assertion is wrong but reason is correct statement.

(v) Assertion and reason both are correct statements but reason is not correct explanation of assertion.

0 Follower 3 Views

Payal Gupta

Contributor-Level 10

This is a assertion and reason answer type question as classified in NCERT Exemplar

The S_N² mechanism is demonstrated by the hydrolysis of alkyl halides with inversion of configuration. This is a one-step method that does not need the production of carbocation.

Correct Answer: Option (iii)

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Ten

Assertion- It is difficult to replace chlorine by −OH in chlorobenzene in comparison to that in chloroethane.

Reason: Chlorine-carbon (C−Cl) bond in chlorobenzene has a partial double bond character due to resonance.

(i) Assertion and reason both are correct and reason is correct explanation of assertion.

(ii) Assertion and reason both are wrong statements.

(iii) Assertion is correct but reason is wrong statement.

(iv) Assertion is wrong but reason is correct statement.

(v) Assertion and reason both are correct statements but reason is not correct explanation of assertion.

0 Follower 4 Views

Payal Gupta

Contributor-Level 10

This is a assertion and reason answer type question as classified in NCERT Exemplar

Due to resonance, a partial double bond character occurs in the bond between the C and Cl atoms in chlorobenzene, and we all know that changing a partial double bond character is more difficult than replacing a single bond as in the C - Cl bond in chloroethane.

Correct Answer: Option (i)

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Ten

Assertion: Aryl iodides can be prepared by reaction of arenes with iodine in the presence of an oxidising agent.

Reason : Oxidising agent oxidises I₂ into HI.

(i) Assertion and reason both are correct and reason is correct explanation of assertion.

(ii) Assertion and reason both are wrong statements.

(iii) Assertion is correct but reason is wrong statement.

(iv) Assertion is wrong but reason is correct statement.

(v) Assertion and reason both are correct statements but reason is not correct explanation of assertion.

0 Follower 2 Views

Payal Gupta

Contributor-Level 10

This is a assertion and reason answer type question as classified in NCERT Exemplar

Oxidising chemicals such as HIO₃ oxidise HI to I₂ because the presence of HI causes the aryl iodides to revert to arenes in their absence.

Correct Answer: Option (iii)

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Ten

Assertion : In monohaloarenes, further electrophilic substitution occurs at ortho and para positions.

Reason : Halogen atom is a ring deactivator.

(i) Assertion and reason both are correct and reason is correct explanation of assertion.

(ii) Assertion and reason both are wrong statements.

(iii) Assertion is correct but reason is wrong statement.

(iv) Assertion is wrong but reason is correct statement.

(v) Assertion and reason both are correct statements but reason is not correct explanation of assertion.

0 Follower 3 Views

Payal Gupta

Contributor-Level 10

This is a assertion and reason answer type question as classified in NCERT Exemplar

Because halogen atoms are ortho and para directing, rather than ring deactivators, further electrophilic substitution occurs at ortho and para locations.

Correct Answer: Option (v)

0 0

New answer posted

9 months ago

Ncert Solutions Chemistry Class 12th Chemistry NCERT Exemplar Solutions Class 12th Chapter Ten

Assertion: Presence of a nitro group at ortho or para position increases the reactivity of haloarenes towards nucleophilic substitution.

Reason : Nitro group, being an electron withdrawing group decreases the electron density over the benzene ring.

(i) Assertion and reason both are correct and reason is correct explanation of assertion.

(ii) Assertion and reason both are wrong statements.

(iii) Assertion is correct but reason is wrong statement.

(iv) Assertion is wrong but reason is correct statement.

(v) Assertion and reason both are correct statements but reason is not correct explanation of assertion.

0 Follower 6 Views

Payal Gupta

Contributor-Level 10

This is a assertion and reason answer type question as classified in NCERT Exemplar

The nitro group on the ortho and para positions of haloarenes acts as an electron-withdrawing group, making it more reactive to nucleophilic substitution reactions due to the electron deficit.

Correct Answer: Option (i)

0 0

Get authentic answers from experts, students and alumni that you won't find anywhere else

On Shiksha, get access to

66k Colleges
1.2k Exams
687k Reviews
1800k Answers

Community GuidelinesUser Points System

QuestionsDiscussionsTags

Need guidance on career and education? Ask our experts

Your Question

Ncert Solutions Chemistry Class 12th

Questions

Discussions

Active Users

Followers

All

Discussions

Unanswered Questions

Share Your College Life Experience