ECAT Pre Engineering MCQ Test With Answer for Chemistry Full Book

By simply reacting Grignand's reagent with water we get

• An alkane A
• Higher alkane B
• An alkene C
• An alkyne D

During nitration of benzene, the active nitrating agent is

• NO3 A
• NO2+ B
• NO2- C
• HNO3 D

Where lime is not used

• In refining or metals A
• In paper industry B
• In glass industry C
• In the preparation of NaOH D

Wohler succeeded in obtaining, urea from

• Cyanogen A
• Ammonium cyanate B
• Ammonium hydroxide C
• None of these D

BOD is the oxygen demand with in days(s):

• Four A
• Two B
• Three C
• Five D

In the extraction of iron, slag is produced which is

• CO A
• FeSiO₃ B
• MgSiO₃ C
• CaSiO₃ D

Contamination of water of tanning industries is due to:

• Cr(III) A
• Cr(VI) B
• Mn(III) C
• Mn(VII) D

• -1.10 V A
• +1.10 V B
• -0.42 V C
• +0.42 V D

Which of the following statements is no correct regarding bonding molecular orbitals?

• Bonding molecular orbitals possess ls energy than atomic orbitals from which they are formed. A
• Bonding molecular orbitals have low electron density between the two nuclei. B
• Every electron in bonding molecular orbitals contributes to the attraction b.w atoms. C
• Bonding molecular orbitals are formed when the electron waves undergo constructive interference. D

Size of an anion is increased as compared to its atom because of the

• Addition of new shell A
• Repulsion of electrons in the valence shell B
• Decrease in nuclear charge C
• Increase in the unclear charge D

Number of molecules in one dm³ of water is close to :

• 6.02/22.4

  
  

  A

• 12.04/22.4 *10²³

  
  

  B

• 18/22.4*10²³

  C

• 55.6*6.02*10²³ * 10²³

  D

The wave number of light emitted by a certain source is 2 x 10⁵m. The wavelength of this light will be:

• 500 NM. A
• 500 M. B
• 200 NM. C
• 5 x 10⁷m D

In microwave own , the wave energy produced in absorbed by certain polar molecule, On which molecule out of the given molecules would maximum energy?

• SiO2 A
• NaCl B
• C2H5OH C
• None of these D

Maximum variable oxidation state is of:

• Mn⁺² A
• Fe⁺³ B
• Cr⁺¹ C
• a and b D

In a reversible reaction, two substances are in equilibrium. If the concentration of each one is reduced to half, the equilibrium constant will be

• Reduced to half of its original value A
• Doubled B
• Same C
• Reduced to one fourth its original value D

The nature of positive ray depend on:

• The nature of electrode. A
• The nature of discharge tube. B
• The nature of residual gas. C
• All of above. D

Ionization energy depends upon

• Nuclear charge A
• Atomic size B
• Shielding effect C
• All of the above D

Acetal is produced by reacting alcohol in the presence of dry HCl with

• Acetaldehyde A
• Ketone B
• Ether C
• Carboxylic acid D

When a colourless gas is passed through bromine water only decolourisation takes place the gas is

• SO₂ A
• HBR B
• HCl C
• H₂S D

Bakelite is obtained from phenol by reacting with

• Acetaldehyde A
• Acetal B
• Formaldehyde C
• Chlorobenzene D

Which one of the following statement is wrong regarding differences between aldehydes and ketones

• Aldehydes undergo reduction to form primary alcohols while ketones undergo reduction to form secondary alcohols A
• Aldehydes undergo oxidation to form acids having less number of carbon atoms while ketones undergo oxidation to form acids having same number of carbon atoms B
• Aldehydes give positive silver mirror test while ketones give negative -mirror test C
• Aldehydes can undergo polymerization while ketones cannot undergo polymerizarion D

In endothermic reactions, the heat content of the

• Products is more than that of reactants A
• Reactants is more than that of products B
• Both a and b C
• None of the above D

β-D-glucose is a monomer for

• Strach A
• Cellulose B
• Glycogen C
• Protein D

Complete reduction of acids to alkanes is carried out with?

• Hydrogen iodide A
• Red phosphorous B
• Lithimum ammonium hydride C
• Both B and C D

The rate of reaction :

• Remain same as reaction proceeds. A
• May decrease or increase as reaction proceeds . B
• Increase as reaction proceeds. C
• Decreases as reaction proceeds. D

Which one of the following compounds does not have the empirical formula CH₂O?

• Ethanoic acid, CH₃CO₂H A
• Ethanol, CH₃CH₂OH B
• Glucose, C₆H₁₂O₆ C
• Methanal, HCHO D

NaBH₄and LialH₄are

• Ionic hydrides A
• Covalent hydrides B
• Interposal hydrides C
• Complex hydrides D

The homologous series of aldehydes and ketones have general formula:

• C_nH_2nO A
• C_nH_nO B
• C_nH_2n-1O C
• C_nH_nO_n D

In the expression rate = K [A]^a[B]^bK is

• The order of reaction A
• The speed of reaction B
• The specific rate constant C
• The overall order of reaction D

The substance added in the paints for improving the mechanical properties is called

• Pigment A
• Filter B
• Stabilizer C
• Binder D