ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

Orbital having same energy is called:

• Hybrid orbital. A
• Valence orbital. B
• Degenerate orbital. C
• D-orbital. D

The wave length of electron as wave is 0.5 nm. What is the wave length in meter

• 5 x 10^-9 A
• 5 x 10^-12 B
• 5 x 10^-6 C
• 5 x 10^-10 D

The value of charge on electron is

• 1.602 x 10^-19coulombs A
• 1.602 x 10^-18coulombs B
• 1.602 x 10^-17coulombs C
• 1.602 x 10^-16 coulombs D

For principle quantum number n=4, the total number of orbitals having l = 3 is

• 3 A
• 7 B
• 5 C
• 9 D

Cathode rays drive a small paddle wheel placed in their path. This observation shows that

• Cathode rays travel in straight lines A
• Cathode rays are negatively charged B
• Cathode rays produce x-rays C
• Cathode rays are material particles having momentum D

The radius of first orbit of H-atom is

• 4.75 A° A
• 3.84 A° B
• 8.4 A° C
• 0.529 A° D

The order of frequency of the following radiations unltraviolet, visible, infrared and microwave is

• Microwave > infrared > visible > ultraviolet A
• Visible > ultraviolet > microwave > infrared B
• Ultraviolet > visible > infrared > microwave C
• Infrared > microwave > ultraviolet > visible D

Which have better penetrating power

• Alpha rays A
• Beta rays B
• Gamma rays C
• X-rays D

Rutherford's atomic model suggests the existence of

• Atom A
• Nucleus B
• alpha particle C
• Measons D

The range of visible spectrum is

• 300 - 600 nm A
• 600 - 900 nm B
• 400 - 750 nm C
• 100 - 300 nm D

Which of the following was discovered first:

• Charge to mass ratio of electrons. A
• Mass of electrons. B
• Charge of electrons. C
• All of above at same time. D

When the electron jumps form second third, fourth orbit to the fist orbit, the transitions are known as

• Balmer series A
• Lyman series B
• Pfund series C
• Brackett series D

The radius of second Bohr's orbit is

• 0.053 nm A
• 0.053/4 nm B
• 0.053 x 4 nm C
• 0.053 x 20 nm D

Which of the following element's outermost orbits last electron has magnetic quantum number m=0?

• Na A
• O B
• Cl C
• N 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

The number of electrons in the M shell of the element with atomic number 24 is

• 24 A
• 12 B
• 13 C
• 8 D

The valence orbital configuration of an element with atomic number 23 is

• 3d⁵ A
• 3d³, 4s² B
• 3d³, 4s¹, 4p¹ C
• 3d²,4s²,4p¹ D

The ratio of the ionization energy of H and Be³⁺is

• 1 : 1 A
• 1 : 3 B
• 1 : 9 C
• 1 : 16 D

Photons of yellow colour are ______ energetic than violet colour

• More A
• Less B
• Equal C
• None D

Electrons arranged in orbitals according to the increasing order of their n + l values, this rule is named as

• Hund's rule A
• Heisenberg's principle B
• Paulit exclusion principle C
• Auf bau principle D

The total values of magnetic quantum number of subshell are five, the subshell is

• S-subshell A
• P-subshell B
• D-subshell C
• F-subshell 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

The nature of positive rays depend on:

• Nature of discharge tube. A
• Nature of resident gas. B
• Nature of electrode. C
• All of above. D

• Neutrons are attracted by nucleus A
• Neutrons carry out nuclear reactions B
• Neutrons carry no charge C
• Neutrons are electromagnetic radiations D

The nature of the positive rays depend on

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

In the atomic emission spectrum the lines which appear bright, appear dark in absorption spectrum because

• The radiations emitted in emission spectrum are absorbed in absorption spectrum A
• Atomic emission spectrum is continuous B
• Atomic absorption spectrum is continuous C
• Distance between the lines increases D

The order of distance between the various Bohr orbits is

• r₂- r₁> r₃- r₂> r₄- r₃> ...... A
• r₁> r₂> r₂- r₃> r₄-r₃> ..... B
• r₂-r₁= r₃- r₂= r₄- r₃> ..... C
• r₂- r₁> r₃- r₂< r₄- r₃< .... D

The symbol of the element whose atoms have the outer most electronic configuration 2s²2p³is

• N A
• Li B
• P C
• Na D

The radiations with wavelength shorter than violet light are called

• Ultraviolet A
• Infrared B
• Microwave C
• Radio frequency D

The experimental evidences for the existence of atomic nucleus comes from:

• Line spectrum of hydrogen. A
• Magnetic bonding of cathode rays. B
• Millikan oil drop experiment. C
• Scattering of alpha particles by thin metal foil. D