ECAT Pre Engineering Chemistry Chapter 1 MCQ Test With Answer

A compound contains one atom of oxygen and % of O 34.78, then molecular mass of compound is

• 46 A
• 78 B
• 110 C
• 180 D

When an electron is added to a uni positive ion we get:

• Cation A
• Molecule B
• Neutral atom C
• Anion D

Isotopes differ in the

• Number of neutrons A
• Number of protons B
• Number of electrons C
• Number of atoms D

The percentage of which element in the organic compound is determined by the difference method

• Carbon A
• Hydrogen B
• Nitrogen C
• Oxygen D

The amount of products obtained from the balanced chemical equation is regarded as

• Theoretical yield A
• Actual yield B
• % yield C
• Experimental yield D

The percentage of H is the highest in

• CH₄ A
• NH₃ B
• H₂SO₄ C
• C₆H₁₂O₆ D

Which one of the following step is not involved in determination of empirical formula

• Determination % of each element A
• Determination of gram atom of each element B
• Determination of isotopes of each element C
• Determination of atomic ratio of element D

The mass of Al₂S₃formed when 20 grams Al reacts completely with S is

• 60 g A
• 50 g B
• 50.55 g C
• 55.55 g D

Determination of atomic masses and invention of system of writing symbols was made by:

• J. Berzelius A
• Democritus B
• Dalton C
• None of above D

One mole of SO₂contains

• 6.02 x 10²³atoms of oxygen A
• 18.1 x 10²³, molecules of SO₂ B
• 6.02 x 10²³ atoms of sulphur C
• 4 gram atoms of SO₂ D

The phenomenon of isotropy was first discovered by

• Soddy A
• Rutherford B
• Bohr C
• Dalton D

CL₂, N₂ and O_{2 are:}

• Diatomic molecules

  A

• Hetero atomic molecules

  B

• Poly-atomic molecules

  C
• Mono-atomic molecules D

Formation of a cation is:

• Exothermic process A
• Non-endothermic process B
• Endothermic process C
• None of above D

A beaker contains 9 grams of water. The number of H-atoms is

• 6.02 x 1023 A
• 3.01 x 1023 B
• 6.02 x 1024 C
• 3.01 x 1024 D

0.5 mole of CH4and 0.5 mole of SO2gases have equal

• Volume A
• Mass in grams B
• Total number of atoms C
• Number of molecules D

• N₂O₄is limiting reactant A
• N₂H₄is the limiting reactant B
• Reactants are completely converted to the products C
• Reactions is reversible D

A molecular ion is formed by

• Passing a high energy electron beam through gaseous molecule A
• Dissolving a salt i dilute acid B
• Passing electric current through molten salt C
• Passing electricity through aqueous solutions D

Which has greater number of moles

• 0.1 g sodium A
• 6.02 x 10²⁰atoms of magnesium B
• 20 cm³0.1mole per dm³of NaOH C
• 12.2 dm³of nitrogen at standard
  [A_rNa = 23, Mg = 24, O = 16]
  D

Which statement about molecule is incorrect ?

• Molecules of a substance are similar A
• Hemoglobin is a homo atomic molecules B
• Oxygen molecule is a macro molecule C
• It exist independently D

Covalent compound s mostly exist in the form of:

• Protons

  A

• Atoms

  B
• Neutrons C

• Molecules

  D

C₆H₁₂O₆and C₁₂H₂₂O₁₁ are:

• Mono-atomic molecules A
• Diatomic molecules B
• Poly-atomic molecules C

• Hetero atomic molecules

  D

Which statement about an atom is true ?

• The number of neutrons is not equal to number of electrons A
• Mass number is less than atomic number B
• All the elements have only one mass number C
• Mass number can be equal to atomic number D

A limiting reactant is one which according to the stoichiometric equation

• Has excess mass A
• Has least mass B
• Has excess number of moles C
• Has least number of moles D

Mass spectrometer measures the

• Exact mass of an element A
• Average mass of an element B
• The number of elements present in a molecule C
• m/e value of a positive ion D

What is the volume in cm³of 3.01 x 10²³molecules of O₂gas at S.T.P

• 1000 cm³ A
• 11000 cm³ B
• 1120 cm³ C
• 11200 cm³ D

A compound having empirical formula C₃H₃O and its molecular mass is 110.02. Its molecular formula is

• C₃H₃O A
• C₆H₆O₂ B
• C₉H₉O₃ C
• C₃H₆O₂ D

The relative atomic mass of chlorine is 35.5. What is the mass of 2 mol of chlorine gas

• 142 g A
• 71 g B
• 35.5 g C
• 18.75 g D

He Ar and Ne are:

• Mono-atomic molecules A

• Hetero atomic molecules

  B

• Poly-atomic molecules

  C

• Diatomic molecules

  D

One mole of ethanol and one mole of ethane have an equal

• Mass A
• Number of atoms B
• Number of electrons C
• Number of molecules D

• 32 g A
• 3.2 g B
• 5.6 g C
• 9.6 g D