ECAT Pre Engineering Chemistry Chapter 5 MCQ Test With Answer

The radius of first orbit of hydrogen atom

• 0.329 A° A
• 0.429 A° B
• 0.529 A° C
• 0.229 A° D

Energy of electron in the infinite Bohr orbit of H-atom is

• 0 KJ/mole A
• 1 KJ/mole B
• -1 KJ/mole C
• -1313.32 KJ/mole D

The uncertainty principle was stated only

• De Brogilie A
• Heinsenberg B
• Einstein C
• Schrodinger D

The range of visible spectrum is

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

Energy of electron in an orbit according to Bohr theory is negative due to

• Repulsion of electrons in the same orb A
• At infinity energy is zero ad a traction towards nucleus decreases energy B
• Electron has negative charge C
• Product of positive nuclear charge and negative charge is negative D

Quantum number value for 2p orbitals are:

• n=2 ,l=1 A
• n=1 ,l=2 B
• n= ,l=0 C
• n=2 ,l=0 D

For a 3P subshell the set of principle and azimuthal quantum number is

• n = 1 , l = 2 A
• n = 3, l = 0 B
• n = 3, l = 1 C
• n = 1, l = 3 D

No cathode rays are produced in the discharged tube when gas is under ordinary pressure even if voltage of 5000 to 10000 is applies. This reason is

• Voltage is low A
• Discharge tube is not coloured B
• Gas does not conduct current under ordinary pressure C
• Temperature low D

An electron has principal quantum number 3. The number of its 1 subshell and 2 orbitals would be respectively

• 3 and 5 A
• 3 and 7 B
• 3 and 9 C
• 2 and 5 D

Charge of an electron is:

• 1.6 x 10^-19 C

  A

• 9.1 x 10^-34 C

  B

• 1.7588 x 10¹¹ C

  C

• 6.62 x 10^-34 C

  D

Pauli's principle is applicable to

• Degenerate orbits A
• Two electrons in the same orbital B
• One electron C
• None D

A 4f orbital has

• one node A
• two node B
• three node C
• four nodes 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

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

Charge on electron was discovered by:

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

Rutherford's atomic model suggests the existence of

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

Which of the following orbitals have a dumb bell shape?

• s A
• p B
• d C
• f D

The limiting line of Blamer series in hydrogen spectrum lies in

• Visible regions A
• Ultraviolet region B
• Infrared region C
• x-rays region D

The number of neutrons in the element ⁹₄Be is

• 4 A
• 5 B
• 9 C
• 13 D

Positive particle in discharged tube is produced by ionization of gas molecules, which is caused by

• Gas molecules collide with anode A
• Gas molecules are at high temperature B
• Gas molecules produce X-rays C
• Cathode rays remove electrons from gas molecules D

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

The four quantum numbers of the valency electron of potassium are

• 4,1,1,1/2 A
• 4,0,0,1/2 B
• 4,1,0,1/2 C
• 4,4,0,1/2 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

Heaviest particle is

• Meson A
• Neutron B
• Proton C
• Electron D

1 erg of energy corresponds to

• 6.02 x 10²³J/mol A
• 6.02 x 10¹⁶J/mol B
• 1 erg/mol C
• 10^-7J/mol D

Balmer's series is in ______ region

• Visible A
• U V B
• I. R. C
• None D

Find the magnetic moment of a divalent ion in aqueous solution if its atomic number is 25

• 3.0 BM A
• 4.9 BM B
• 5.9 BM C
• 6.9 BM D

The atomic number of an element is 35 what is the total number of electrons present in all the p-orbitals of the ground state atom of that element?

• 6 A
• 11 B
• 17 C
• 23 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

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