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Nucleophile

Nucleophile

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Q.

Gaseous benzene reacts with hydrogen gas in presence of a nickel catalyst to form gaseous cyclohexane according to the reaction: $C_{6} H_{6} (g) + 3 H_{2} (g) \to C_{6} H_{12} (g) .$ A mixture of $C_{6} H_{6}$ and excess $H_{2}$ has a pressure of 60 mm of Hg in an unknown volume. After the gas has been passed over a nickel catalyst and all benzene converted to cyclohexane, the pressure of the gas was 30 mm of Hg at same volume and temperature. The fraction of $C_{6} H_{6}$ (by volume) present in the original volume is___.

1/3
1/4
1/5
1/6

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Q.

S t a t e m e n t - I : - ---------------- -

The canonical forms have no real existence

S t a t e m e n t - I I : - ------------------ -

There is no equilibrium between canonical forms

S t a t e m e n t - I I I : - ------------------- -

The energy of the resonance hybrid is less than the energy of any single canonical structure

S t a t e m e n t - I V : - ------------------ -

The molecule does not exist for a certain fraction of time in one canonical form and for other fraction of time in other canonical form
Correct statements is / are

Only II, III
Only II, IV
All
Only II, III, IV

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Q. calculate the limiting reagent in given reaction s S8+8O2 GIVES 8SO2

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Q. For carbocation CH3+ which of the following is not true (1) it has trigonal planar shape (2) its shape is derived by overlap of each of the three sp2 hybridised orbitals of carbon with corresponding 1s orbital of hydrogen atoms (3) it has one vacant orbital on carbon which is perpendicular to molecular plane (4) it has two vacant p orbital on carbon which are in molecular plane

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Q. Why is

L i F

almost insoluble in water whereas

L i C l

is soluble not only in water but also, in acetone?

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Q. 28. What is reaction intermediate?

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Q. 37. how hybridization pf phosphorous atom comes sp3 in p4 molecule while it makes bond only by p orbitals? SAME THING FOR PH3 MOLECULE TOO?

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Q.

Standard molar enthalpy of formation, $△_{f} H^{⊖}$ is just a special case of enthalpy of reaction , $△_{r} H^{⊖}$ . Is the $△_{r} H^{⊖}$ for the following reaction same as $△_{f} H^{⊖}$ ?Give reason for your answer.

$C a O (s) + C O (g) \to C a C O_{3} (s)$ ;

$△_{f} H^{⊖} = - 178.3 k j m o l^{- 1}$

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Q.

Why is anhydrous AlCl₃ used as catalyst in several organic reactions?

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Q. Which of the following graph is valid for a solution containing phenol and aniline?
Assume that at the given constant temperature of solution, vapour pressure of phenol (A) in pure state is more than that of aniline (B) in pure state.

None of the above

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Q. Gaseous Benzene reacts with hydrogen gas in presence of a Nickel catalyst to form gaseous cyclohexane according to the Reaction

C_{6} H_{6} + 3 H_{2} ⟶ C_{6} H_{12}

A mixture of

C_{6} H_{6}

and excess

H_{2}

has a pressure of 60mm of Hg in an unknown volume. After the gas had been passed over a Ni catalyst and all the benzene converted to cyclohexane, the pressure of the gas was 30mm of Hg in the same volume at the same temperature. The fraction of

C_{6} H_{6}

(by volume) present in the original volume is

1/3
1/4
1/5
1/6

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Q. The nucleophilicities of

R O^{-}

,

H O^{-}

,

R C O O^{-}

, ROH and

H_{2} O

are of the order :

$H O^{-} > R O^{-} > H_{2} O > R O H > R C O O^{-}$
$R O^{-} > H O^{-} > R C O O^{-} > R O H > H_{2} O$
$H_{2} O > R O H > R C O O^{-} > H O^{-} > R O^{-}$
$R O H > H_{2} O > H O^{-} > R C O O^{-} > R O^{-}$

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Q.

Which of the following is not correct?

$O r d e r o f b a s i c i t y O r d e r o f n u c l e o p h i l i c i t y (a) F^{-} > C l^{-} > B r^{-} B r_{-} > C l^{-} > F^{-} (b) H - O - O^{-} > O H^{-} H - O - O^{-} > O H^{-} (c) C H_{3} > N H_{2}^{-} > O H - C H_{3} > N H_{2}^{-} > O H^{-} (d) H_{2} O > H_{2} S H_{2} O < H_{2} S$

$F^{-} > C l^{-} > B r^{-} B r_{-} > C l^{-} > F^{-}$
$H - O - O^{-} > O H^{-} H - O - O^{-} > O H^{-}$
$C H_{3} > N H_{2}^{-} > O H - C H_{3} > N H_{2}^{-} > O H^{-}$
$H_{2} O > H_{2} S H_{2} O < H_{2} S$

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Q.

Which of the following is/are ambident nucleophiles?

$^{-} C \equiv N$
$N O_{2}^{-}$
$P C l_{5}$
$S n C l_{4}$

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Q. Which is correct nucleophilic strength of following nucleophile:

$⊖ O H > C H_{3} C O ⊖ O > ⊖ O C H_{3} > C_{6} H_{5} ⊖ O$
$C H_{3} ⊖ O > C H_{3} C O ⊖ O > C_{6} H_{5} ⊖ O > ⊖ O H$
$C_{6} H_{5} ⊖ O > ⊖ O H > C H_{3} ⊖ O > C H_{3} C O ⊖ O$
$C H_{3} ⊖ O > ⊖ O H > C H_{3} C O ⊖ O > C_{6} H_{5} ⊖ O$

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Q. 1. Which of the following has maximum bond energy?
(a) Cl₂ (b) F₂ (c) Br₂ (d) I₂

2. Which one of the following does not have sp²-hybridized carbon?
(a) CH₃COCH₃ (b) CH₃COOH (c) CH₃ – C ≡ N (d) CH₃CONH₂

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Q. Product (C) of the above reaction is:

1, 3-hexadiene
1, 3-heptadiene
1, 3-butadiene
1, 4-pentadiene

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Q. Cl2+2Br- =2Cl-+Br2 what is the n factor of bromine in displacement reaction with chlorine

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Q. Choose the correct statement(s) :
(Assume complete dissociation/association)

$Van't Hoff factor for B a (O H)_{2} (a q .) is 2$
$Van't Hoff factor for B a (O H)_{2} (a q .) is 3$
$Van't Hoff factor for C H_{3} C O O H in benzene is 2$
$Van't Hoff factor for C H_{3} C O O H in benzene is 0.5$

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Q. Predict the product 'X' and 'Y' of the given reaction.

C H_{4} (g) + H_{2} O (g) 1270 K - --- \to N i^{'} X^{'} +^{'} Y^{'}

$H C H O$ and $H_{2}$
$C O$ and $H_{2}$
$C H_{3} O H$ and $H_{2}$
$C O_{2}$ and $H_{2}$

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