ECAT Pre Engineering MCQ Test With Answer for Chemistry Full Book

Which is the correct electronic configuration of Cr - 24

• 1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁴, 4s² A
• 1s², 2s², 2p⁶, 3s², 3p⁶, 3d³, 4s², 4p¹ B
• 1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁵, 4s¹ C
• 1s², 2s², 2p⁶, 3s², 3p⁶, 3d⁵, 4p¹ D

The best electrode used in salt bridge is KCl. Which other electrolyte an also be used for the purpose :

• NaCl A

• NH₄NO₃

  B

• KNO₃

  C

• NaNO₃

  D

Which statement is not true. A solution is a homogeneous mixture of

• Two ionic substance like NaCl and HCl A
• Two molecular substances sugar and water B
• A solute and a solvent 1% NaHCO₃in water C
• NaCl and sand D

Iodoethane reacts with sodium in ether, the product formed is

• Pentene A
• Propyne B
• Butene C
• Butane D

Mass of simple electron is:

• 9.1 x 10^-31 kg

  A

• 9.1 x 10^-30 kg

  B

• 1.66 x 10^-31 kg

  C

• 9.1 x 10^-31 kg

  D

When we perform the same reaction by taking two different initial concentrations of a reactant for a second order reaction then

• Reaction becomes exothermic A
• Energy of activation is different B
• Mechanism of reaction is changed C
• Half life period is changed D

Ketones are prepared by the oxidation of:

• Primary alcohol A
• Secondary alcohol B
• Tertiary alcohol C
• None of these D

Law of triads was given by:

• Al-Razi A
• Dobriener B
• Newland C
• Mendeleev D

K_spvalue for PbSO₄= 1.8 x 10^-8mole²dm^-6. The maximum concentration of Pb⁺⁺ions is

• 1.34 x 10^-4mole dm^-3 A
• 1.8 x 10^-4 B
• 3.6 x 10^-16mole dm^-3 C
• 1.0 x 10^-8mole dm^-3 D

Acetamide is prepared by

• Heating ammonium acetate A
• Heating methyl cyanide B
• Heating ethyl acetate C
• The hydrolysis of methyl cyanide D

Carboxylic acids functional group is:

• ----COOH A
• ----CO--- B
• ----OH C
• -----COH D

Spectrum of white light is continuous becuase

• Colors separated by dark spaces A
• There are no boundary lines between the colours B
• The radiations are in infrared region C
• The radiatins fall in ultraviolet region D

In the chemical combination of hydrogen and fluorine to form HF:

• Sodium atom donates major share of its electrons. A
• Hydrogen atom donates the major share of its electrons. B
• Both the atoms share the electrons equally. C
• None of above. D

pH of the human blood which is essentially maintained constant due to carbonates, biocarbonates, phosphates etc., is

• 7.00 A
• 7.25 B
• 7.35 C
• 7.47 D

Purification of an impure copper is made by electrolytic cell, in which impure copper is anode and pure copper is cathode, and the electrolyte used is

• H₂SO₄ A
• CuSO₄ B
• ZnSO₄ C
• Na₂SO₄ D

Which is aqua regia?

• HCL : NO A
• HCl : HNO₃ B
• HCl : H₂SO₄ C
• H₂SO₄ : HNO₃ D

Which has garlic like odour?

• N₂O A
• NO B
• NO₂ C
• NH₄ D

• HF is stable and does not decompose even at 2000°C A
• HF is stable and slowly decomposes at 2000°C B
• HF is strong acid C
• HF produces equal moles of hydrogen and fluorine D

• 
  A
• 
  B
• 
  C
• 
  D

In the earth crust sodium is

• 2.50% A
• 2.30% B
• 2.40% C
• 3.50% D

The movement of gas molecules from a region of high pressure to vacuum is called

• Evaportation A
• Effusion B
• Conduction C
• Diffusion D

Odour of alkene is:

• Fruity A
• Odourless B
• Zarlic like C
• Irritating D

An organic compound will decolorise dill acidified (aq) KMnO₄on warming, but will not decolorise bromine water. What is the compound

• KMnO₄ A
• Ethanol B
• Ethane C
• CH₃CH₂Cl D

Which is used as cooling medium in nuclear reactors?

• He A
• Ne B
• Ar C
• Kr D

Which of the following is a characteristic of a reversible reaction?

• It never proceeds to completion A
• It can be influenced by a catalyst B
• It proceeds only in the forward direction C
• Number of moles of reactants and products are equal D

Acetylene had a characteristic ethereal smell resembling that of

• Ginger A
• Vinegar B
• Garlic C
• Onion D

Two different hydrocarbon each contain the same percentage by mass of hydrogen. It follows that they have the same

• Empirical formula A
• Number of atoms in a molecules B
• Number of isomers C
• Relative molecular mass D

• 450°C A
• 250°C B
• 850°C C
• 1000°C D

In electrolysis of NaCl when Pt electrode is taken then H₂is liberated at cathode while with Hg cathode it forms sodium amalgam

• Hg is more inert than Pt A
• More voltage is required to deduce H⁺at Hg than Pt B
• Na is dissolved in Hg while it does not dissolve in Pt C
• Conc. of H⁺ions is larger when Pt electrode is taken D

Which are metalloid?

• Nitrogen and phosphorous A
• Arsenic and phosphorous antimony B
• Phosphorous and arsenic C
• Antimony and bismuth D