ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The radiations with wavelength shorter than violet light are called

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

Number of neutrons in heavy hydrogen atom is

• 0 A
• 1 B
• 2 C
• 3 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 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

Which one of the following particles has amass 1/1836 time, that of hydrogen?

• Neutron. A
• Proton. B
• Electron. C
• Positron. 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 number of de-electrons retained in Fe²⁺ (At.No. of Fe = 26) ions is

• 3 A
• 4 B
• 5 C
• 6 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

Which of the following particles has longest wavelength, if they have same speed:

• Proton. A
• Neutron. B
• Electron. C
• Positron. 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

When electron jumps from n₂= 2,3,4,5,.... orbit to n₁= 1 orbit in the hydrogen atom, the radiations emitted give the spectral lines

• Lyman series A
• Blamer series B
• Paschen series C
• Brackett series D

The velocity of photon is:

• Independent of its wavelength. A
• Depends on its wavelength. B
• Equal to square of its amplitude C
• Depends on its source. D

The quantum number which describe the orientation of the orbitals is

• Spin quantum number A
• Principle quantum number B
• Azimathal quantum number C
• Magnetic quantum number D

Proton was discovered by:

• Chadwick A
• J.J. Rhomson B
• Millikan. C
• Goldstein. D

In which of the following pairs, the numbers of electrons in the outermost shell are different?

• As,Sb A
• Ge,Sn B
• In,pt C
• Se,Te D

The third line of the Balmer series, in the emission spectrum of the hydrogen atom,is due to the transition from the

• Fourth Bohr orbit to the first Bohr orbit A
• Fifth Bohr orbit to the second Bohr orbit B
• Sixth Bohr orbit to the third Bohr orbit C
• Seventh Bohr orbit to the third Bohr orbit D

Rutherford's model of atom failed because:

• The atom did o have a nucleus and electrons A
• It did not account fro the attraction b/w protons and neutrons B
• It did no account for the stability of the atom. C
• There is actually no space b/w the nucleus ad the electrons. D

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

For which of the following sets of quantum numbers and electron will have the highest energy?

• 3,2,1,1/2 A
• 4,2,-1,1/2 B
• 4,1,0,-1/2 C
• 5,0,0,1/2 D

In the ground state of an atom the electron is present

• In the nucleus A
• In the second shell B
• Nearest to the nucleus C
• Farthest from the nucleus D

Splitting of spectral lines of the hydrogen atom under the influence or magnetic field is called

• Stark effect A
• Zeeman effect B
• Compton effect C
• Photoelectric effect D

The value of Plank's constant 'h' is

• 6.625 x 10^-34 A
• 6.625 x 10^-34J sec B
• 6.625 x 10^-34KJ C
• 6.625 x 10^-34K Cal D

The configuration 1s²2s²2p⁵3s¹shows

• Excited state of O₂ A
• Excited state of neon B
• Excited state of fluorine C
• Ground state of fluorine atom D

In the ground state of an atom, the electron is present:

• In the nucleus. A
• In the second shell. B
• Nearest to the nucleus. C
• farthest from the nucleus. D

When potassium metal is exposed to violet light

• Ejection of electrons takes place A
• Ejection of some potassium atoms occurs B
• There is no effect C
• The absorption of electrons takes place D

e/m of cathode rays is same but for positive rays e/m changes by changing gas in the discharge tube because

• Cathode rays are small sized particles A
• Cathode rays have same charge B
• Nature of cathode rays same for all gasses, but masses of nuclei are different for different gases C
• Temperature of cathode rays higher 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

Charge on electron was discovered by:

• Millikan. A
• Crook. B
• Neil Bohr. C
• Rutherford. D

The arrangement of subshells in the ascending order of their energy on complete filing of 4f subshell the entering electrons goes to

• 5s A
• 5p B
• 5d C
• 5f D