Chem quiz

Q.1  A reaction involving two different reactants can never be
       (a) Unimolecular reaction
       (b) First order reaction
       (c) second order reaction
       (d) Bimolecular reaction



Answer (a) Unimolecular reaction

Q.2 Due to the presence of an unpaired electron, free radicals are:
      (a) Chemically reactive
      (b) Chemically inactive
      (c) Anions
      (d) Cations

Answer (a) Chemically reactive

Q.3 Lattice energy of an ionic compounds depends upon
      (a) Charge on the ion only
      (b) Size of the ion only
      (c) Packing of ions only
      (d) Charge on the ion and size of the ion

Answer (d) Charge on the ion and size of the ion

Q.4 The highest electrical conductivity of the following aqueous solutions is of

      (a) 0.1 M acetic acid
      (b) 0.1 M chloroacetic acid
      (c) 0.1 M fluoroacetic acid
      (d) 0.1 M difluoroacetic acid

Answer (d) 0.1 M difluoroacetic acid

Q.5 During the process of electrolytic refining of copper, some metals present as impurity settle as           ‘anode mud’ These are

     (a) Sn and Ag
     (b) Pb and Zn
     (c) Ag and Au
     (d) Fe and Ni

Answer (c) Ag and Au

Chem quiz

Q.1 The water exchange rates for the complex ions follow the order

         (A) [V(H2O)6]2+ > [Co(H2O)6]2+ > [Cr(H2O)6]3+

         (B) [Cr(H2O)6]3+ > [Co(H2O)6]2+ > [V(H2O)6]2+

         (C) [Co(H2O)6]2+ > [Cr(H2O)6]3+  > [V(H2O)6]2+

         (D) [Co(H2O)6]2+ > [V(H2O)6]2+ > [Cr(H2O)6]3+

Ansewr:-D 

Q.2 Based on Wade’s rule, the structure-type of [B₅H₈]⁻ is
        (A) closo
        (B) nido
        (C)  arachno
        (D)  hypho

Ansewr:-B

Q.3  The coordination geometries around the copper ion of plastocyanin (a blue-copper protein) in              oxidized and reduced form, respectively, are
         (A) tetrahedral and square-planar
         (B) square-planar and tetrahedral
         (C) distorted tetrahedral for both
         (D) ideal tetrahedral for both

Answer:-C

Chem quiz

Q.1 Mention the formula to calculate pH of a solution?

 Answer:- In order to calculate the pH of a solution you have to use the formula pH= -log [H+] or pH                    = -log [H3O+]

Q.2 Mention how many millilitre is equal to 1 litre and how many microliter is equal to litre?
Answer:-  1 millilitre = 0.0001 litre
                 1 microliter = 0.0000001 litre

Q.3 Explain what is titration?

Answer:- Titration is a process to determine the molarity of a base or an acid. In this process a reaction is carried out between the known volumes of a solution with a known concentration, against the known volume of a solution with an unknown concentration.

Organic quiz

Q.1 Phenol, when it first reacts with concentrated sulphuric acid and then with concentrated nitric              acid, gives
      (a) 2,4,6-trinitrobenzene
      (b) o-nitrophenol
      (c) p-nitrophenol

      (d) nitrobenzene

Explanation:-

Sulfonation
The reaction of phenol with concentrated sulfuric acid is thermodynamically controlled. At 25°C, the ortho product predominates while at 100°C, the para product is the major product.

Notice that at both 25° and 100°, initially an equilibrium is established. However, at the higher temperature, the equilibrium is destroyed and the more thermodynamically stable product is produced exclusively.

Nitration

Phenol, when treated with dilute nitric acid at room temperature, forms ortho‐ and para‐nitrophenol

Answer (b) o-nitrophenol

Q.2  α-D-(+)-glucose and β-D-(+)-glucose are
       (a) conformers
       (b) epimers
       (c) anomers

       (d) enantiomers

Explanation:-

Anomers are stereoisomers of cyclic sugars that differ in configuration only at the hemiacetal or hemiketal carbon.

Glucose is both an aldehyde at C-1 and an alcohol at C-5. These two groups can react with each other to form a cyclic hemiacetal (glucopyranose).

www2.chemistry.msu.edu

In the hemiacetal, C-1 has become chiral. It can have the OH group either "down" or "up". These two isomers are anomers, and C-1 (the original carbonyl carbon) is the anomeric carbon.

Answer (c) anomers

Q.3 HBr reacts with CH2 = CH – OCH3 under anhydrous conditions at room temperature to give
      (a) CH3CHO and CH3Br
      (b) BrCH2CHO and CH3OH
      (c) BrCH2 – CH2 – OCH3

      (d) H3C – CHBr – OCH3

Explanation:-

Methyl vinyl ether is a very reactive gas. It is hydrolysed rapidly by dilute acids at room temperature to give methanol and aldehyde.

However, under anhydrous conditions at room temperature, it undergoes many addition reactions at the double bond.

Answer (d) H3C – CHBr – OCH3

Basic quiz

Q.1 An atom has 2 electrons in K-shell, 8 electrons in L-shell and 6 electrons in M-shell. The number       of S-electrons present in the element is:

      A.6
      B.4
      C.10

      D.9

Answer:-6

Q.2 The Boltzmann constant K is equal to:
      A. N/R
      B. R/N
      C. 1/NR
      D. NR

Answer:-B


Q.3 Rutherford’s scattering experiment is related to:
      A. Neutron
      B. Nucleus
      C. Proton
      D. Electron

Answer:-B

Mechanism Organic reaction quiz

Q.1 Covalent bonds can be break by
      A.homolytic fission
      B.heterolytic fission
      C.homolytic fusion

      D.both A and B

Answer:-D
Explanation:-

Bond cleavage is the splitting of a chemical bond.

There are two types of bond cleavage: homolytic and heterolytic.

In homolytic cleavage, the two electrons in the bond are divided equally between the products.





In heterolytic cleavage, one atom gets both of the shared electrons.

Q.2 Formation of radicals which attack reactants molecules generate more free radicals. This step is a       A.initiation step
       B.propagation step
       C.termination step
       D.elimination step

Answer:-B

Q.3 An acceptor of pair of electron is termed as
      A.nucleophile
      B.electrophile
      C.carbocation
      D.anion

Answer:-B

Q.4 In a free radical reaction, free radicals are formed at
      A.initiation step
      B.propagation step
      C.termination step

      D.both A and B

Answer:-D