Q&A - Ask Doubts and Get Answers

Sort by :
Q
Engineering
288 Views   |  

In Carius method of estimation of halogen, 0.15 g of an organic compound gave 0.12 g of AgBr. The percentage of Bromine in the compound is 

  • Option 1)

    34.04

  • Option 2)

    60

  • Option 3)

    30

  • Option 4)

    20

 
As we discussed in concept Carius method test for halogens - - wherein    Carius method is used for the estimation of halogen                                       = 34.04 g   Option 1) 34.04 This option is correct. Option 2) 60 This option is incorrect. Option 3) 30 This option is incorrect. Option 4) 20 This option is incorrect.
Engineering
177 Views   |  

If esterification of (-) lactic acid with CH3OH gives (+) methyl lactete (where - COOH of acid gets coverted to - COOR). Which statement is incorrect?

  • Option 1)

    Configuration has changed.

  • Option 2)

    Direction of rotation has changed.

  • Option 3)

    Configuration doesn't change.

  • Option 4)

    None of these

 
As we learnt in  Nucleophilic Substitution Reaction - SN1substitution nucleophilic unimolecular reaction. These reactions proceed in two steps. - wherein Configuration of molecule doesn't change. Option 1) Configuration has changed. Incorrect Option 2) Direction of rotation has changed. Incorrect Option 3) Configuration doesn't change. Correct Option 4) None of these Incorrect
Engineering
262 Views   |  

A substance which is insoluble in water and possesses a vapour pressure of 10-15 mm Hg at 373K can be conveniently purified by

  • Option 1)

    Sublimation        

  • Option 2)

    Crystallization

  • Option 3)

    Distillation

  • Option 4)

    Steam distillation

 
As we discussed in concept Steam Distillation - This method is used to separate substances which are steam volatile and are immiscible with water. - wherein e.g.   O-nitrophenol and P-nitrophenol    Those substance which is insoluble in water and possesses a vapour pressure of 10-15 mm Hg at 371K can be purified by steam distillation. Option 1) Sublimation         This option is...
Engineering
125 Views   |  

1-Butyne\overset{2[H]}{\rightarrow}A\xrightarrow[BenzoylPeroxide]{Hcl\ in}B\xrightarrow[KOH]{Alc}C, \, \, C\, \, \, is

  • Option 1)

    1-butene

  • Option 2)

    2-butene

  • Option 3)

    1-butyne

  • Option 4)

    2-butyne

 
As we learnt in  Reaction of alkyl halide with KOH (alc) - - elimination reaction take place and produces alkenes. - wherein   Option 1) 1-butene This option is incorrect. Option 2) 2-butene This option is correct. Option 3) 1-butyne This option is incorrect. Option 4) 2-butyne This option is incorrect.
Engineering
876 Views   |  

1 - phenyl - 2 - chloropropane on treating with alcoholic KOH gives

  • Option 1)

    1 - phenyl propane

  • Option 2)

    3 - phenyl propane

  • Option 3)

    1 - phenyl propanol - 2 

  • Option 4)

    1 - phenyl propanol - 1

 
As we learnt in  Reaction of alkyl halide with KOH (alc) - - elimination reaction take place and produces alkenes. - wherein   Option 1) 1 - phenyl propane Option is Correct Option 2) 3 - phenyl propane Option is incorrect Option 3) 1 - phenyl propanol - 2  Option is incorrect Option 4) 1 - phenyl propanol - 1 Option is incorrect
Engineering
107 Views   |  

What is C?

  • Option 1)

  • Option 2)

  • Option 3)

  • Option 4)

 
As we learnt in  Reaction of alkyl halide with aquous KOH - Alkyl halide when treated with Ag KOH Alcohol is obtained. -   Option 1) Option is correct Option 2) Option is incorrect Option 3) Option is incorrect Option 4) Option is incorrect
Engineering
130 Views   |  

What is A?

  • Option 1)

    Cis - 2 - butene

  • Option 2)

    Trans - 2 - butene

  • Option 3)

    1 - butene

  • Option 4)

    Butene

 
As we learnt in  Reaction of alkyl halide with KOH (alc) - - elimination reaction take place and produces alkenes. - wherein Potassium tertiary butoxide is bulky base, hence, show anti-elimination reaction  Option 1) Cis - 2 - butene Option is incorrect Option 2) Trans - 2 - butene Option is incorrect Option 3) 1 - butene Option is correct Option 4) Butene Option is incorrect
Engineering
109 Views   |  

What is true for A?

  • Option 1)

    It is formed by E2 mechanism.

  • Option 2)

    It can't show geometrical isomerism.

  • Option 3)

    It is formed by E1 mechanism.

  • Option 4)

    Loss of H+ occur from 3rd carbon.

 
As we learnt in Reaction of alkyl halide with sodium alkoxide - This reaction is known as Willimnson's Synthesis. - wherein   But-1-ene do not show geometrical isomerism. Option 1) It is formed by E2 mechanism. This option is incorrect Option 2) It can't show geometrical isomerism. This option is correct Option 3) It is formed by E1 mechanism. This option is incorrect Option 4) Loss of H+...
Engineering
132 Views   |  

A and B are:

  • Option 1)

  • Option 2)

  • Option 3)

  • Option 4)

    None of these

 
As we learnt in Reaction of alkyl halide with aquous KOH - Alkyl halide when treated with Ag KOH Alcohol is obtained. -  Cl2 is more reactive but less selective. Option 1) This option is incorrect Option 2) This option is correct Option 3) This option is incorrect Option 4) None of these This option is incorrect
Engineering
130 Views   |  

Which is correct w.r.t. (A) and (B)?

  • Option 1)

    Rate of E2 reaction will be slower for B.

  • Option 2)

    Rate of E2 reaction will be slower for A.

  • Option 3)

    Rate of E1 reaction will be different for A and B.

  • Option 4)

    Rate of E1 reaction will be more for A in comparison to B.

 
As we learnt in Reaction of alkyl halide with KOH (alc) - - elimination reaction take place and produces alkenes. - wherein    E2 - reaction show isotopic effect. C-D bond strength is greater than C-H bond strength. Hence, E2 reaction for B will be slower. Option 1) Rate of E2 reaction will be slower for B. This option is correct Option 2) Rate of E2 reaction will be slower for A. This option...
Engineering
95 Views   |  

Product A will be

  • Option 1)

  • Option 2)

  • Option 3)

  • Option 4)

 
As learnt in Nucleophilic Substitution Reaction - SN1substitution nucleophilic unimolecular reaction. These reactions proceed in two steps. - wherein    Option 1) Incorrect Option 2) Correct Option 3) Incorrect Option 4) Incorrect
Engineering
105 Views   |  

A is

  • Option 1)

  • Option 2)

  • Option 3)

  • Option 4)

 
As learnt in Reaction of alkyl halide with aquous KOH - Alkyl halide when treated with Ag KOH Alcohol is obtained. -  Cl- present at sp2 Carbon show resonance and double bond character exists between Cl- and Carbon. Option 1) Incorrect Option 2) Correct Option 3) Incorrect Option 4) Incorrect
Engineering
102 Views   |  

\lim_{x \to b}\frac{\sqrt{x-a}-\sqrt{b-a}}{x^{2}-b^{2}}

  • Option 1)

    \frac{1}{4b\sqrt{a-b}}

  • Option 2)

    \frac{1}{4b\sqrt{b-a}}

  • Option 3)

    \frac{1}{4a\sqrt{a-b}}

  • Option 4)

    \frac{1}{b\sqrt{b-a}}

 
As we learnt in Method of Rationalisation - Rationalisation method is used when we have RADICAL SIGNS in an expression.(like  1/2,  1/3 etc) and there exists a negative sign between two terms of an algebraic expression. - wherein                 Option 1) Incorrect Option 2) Correct Option 3) Incorrect Option 4) Incorrect
Engineering
99 Views   |  

The degree of dissociation of CH3COOH is influenced by

  • Option 1)

    HCl

  • Option 2)

    CH3COONa

  • Option 3)

    NH4OH

  • Option 4)

    Either of these 

 
As we learnt in Le Chatelier's Principle - It states that a change in any of the factors that determine the equilibrium condition of a system will cause the system to change in such a manner to reduce or to counteract the effect of change. -    Introduction of any electrolyte that shares a common ion will affect the degree of dissociation. HCl, CHCOONa and NH4OH all have an ion common with...
Engineering
1199 Views   |  

Sulphide ions in alkaline solution react with solid sulphur to form polyvalent sulphide ions. The equikibrium constant for the formation of C and S32- from S and S2- ions are 1.7 and 5.3 respectively. Equilibrium constant for the formation of S32-   from  S32-  and S is

 

  • Option 1)

    1.33

  • Option 2)

    3.11

  • Option 3)

    4.21

  • Option 4)

    1.63

 
As we learnt in Law of Chemical equilibrium - At a given temperature, the product of concentration of the reaction products raised to the respective stoichiometric coefficient in the balanced chemical equation divided by the product of concentration of the reactants raised to their individual stoichiometric coefficients has a constant value. - wherein are equilibrium concentration     Given...
Engineering
281 Views   |  

Which species acts as stronger acid than formic acid in aqueous solution?

  • Option 1)

    CH3COOH

  • Option 2)

    H2SO4

  • Option 3)

    NH_{4}^{+}

  • Option 4)

    HPO_{4}^{2-}

 
As learnt in Ionization constant of weak acids - Consider    - wherein     The strength of an acid is determined by the stability of its conjugate base.  has more delocalization of -ve charge than  and is more stable So  is stronger acid than  Option 1) CH3COOH This solution is incorrect Option 2) H2SO4 This solution is correct Option 3) This solution is incorrect Option 4) This...
Engineering
94 Views   |  

Which is not amphoteric?

  • Option 1)

    HSO_{4}^{-}

  • Option 2)

    HCO_{3}^{-}

  • Option 3)

    H_{2}PO_{4}^{-}

  • Option 4)

    HCOO^{-}

 
As learnt in Ionization reaction of dibasic acid - - wherein    are called first and second ionization constant.   Of all the species given,  is the only one that cannot donate a proton and act as an acid. All of these can accept a proton thereby acting as a lease. Option 1) This solution is incorrect. Option 2) This solution is incorrect. Option 3) This solution is...
Engineering
180 Views   |  

Which is correct w.r.t non-ideal solution?

  • Option 1)

    Solution obeys Raoult's Law over the entire range of concentration. 

  • Option 2)

    The vapour pressure is always higher than that predicted by Raoult's Law

  • Option 3)

    The cause for the deviations lie in the nature of interactions at the molecular level

  • Option 4)

    All of these

 
As learnt in Condition for positive deviation - When A - A interactions and B - B  interactions  are  stronger than A - B interactions. e.g. Ethanol + water - wherein     Condition for negative deviation - When A - A interactions and B - B  interactions  are  weaker than A - B interactions. e.g. Acetone + Chloroform - wherein   Any solution that shows deviation from Raoult's law is...
Engineering
99 Views   |  

When 20g of CaCO3 were put into 10 litre of flask and heated to 8000 C , 35% of CaCO3 remained unreacted at equlibrium. KP for decomposition of CaCO is :

  • Option 1)

    1.145 atm

  • Option 2)

    0.145 atm

  • Option 3)

    2.145 atm

  • Option 4)

    3.145 atm

 
As learnt in Equilibrium constant in gaseous system - For equilibrium involving gases, it is usually more convenient to express the equilibrium constant in terms of partial pressure.  - wherein The ideal gas equation is written as                        At t=0                  0.2 At equilibrium     0.2*0.35                        0.2* 0.65             0.2* 0.65     Option 1) 1.145...
Engineering
104 Views   |  

What is the PH of a 1M CH3COONa? Ka of acetic acid=1.8x10-5,Kw=10-14 mol2/l2

  • Option 1)

    2.4

  • Option 2)

    3.6

  • Option 3)

    4.8

  • Option 4)

    9.4

 
As learnt in Ionization constant of weak acids - Consider    - wherein        or    Option 1) 2.4 This solution is incorrect Option 2) 3.6 This solution is incorrect Option 3) 4.8 This solution is incorrect Option 4) 9.4 This solution is correct
Exams
Articles
Questions