All Free Chemistry MCQs with Answers

• A. 1.0974 x 10^7m-1
• B. 1.0974 x 10^-7m-1
• C. 1.0974 x 10^6m-1
• D. 1.0974 x 10^-6m-1

Explanation: The Rydberg constant is like the VIP pass to the atomic world. It's around 1.097 x 10^7 per meter, and it's super important in figuring…

• A. Paschen series is emitted
• B. Balmer series is emitted
• C. Lyman series is emitted
• D. Brackett series is emitted

Explanation: The transition of an electron from a higher orbit to the third orbit in a hydrogen atom corresponds to the Paschen series.

• A. Sodium vapour
• B. Atomic hydrogen
• C. Molten iron
• D. Mercury vapour lamp

Explanation: Absorption spectrum is a type of spectrum in which electron absorbs energy from a source to go from lower energy level to higher energy…

• A. Continuous spectrum
• B. Band spectrum
• C. Line spectrum
• D. None of these

Explanation: When the radiations emitted from a hydrogen-filled discharge tube are passed through a prism or a diffraction grating, they produce a…

• A. rh / 2π
• B. nh / 2π
• C. 2πn / h
• D. 2πr / h

Explanation: nh / 2π is the answer to this, just a factual recall. This is the correct expression representing Bohr's quantisation of angular momentum…

• A. UV
• B. IR
• C. Visible
• D. Microwaves

Explanation: Balmar series are then only lines that lie in visible region.

• A. Lyman
• B. Balmer
• C. Visible
• D. Infrared

Explanation: Correct option is B. The Balmer series is the name given to a series of spectral emission lines of the hydrogen atom that result from…

• A. hc/(E1 - E2)
• B. h/(E1 - E2)
• C. h/c(E1 - E2)
• D. (E1 - E2)/hc

Explanation: But as per ptb, the energy change is given by ∆E=E2-E1∆E=hv∆E=hc/λ E2- E1=hc/λ λ =hc/E2- E1 Ans

• A. n3 → n2
• B. n4 → n3
• C. n5 → n4
• D. n6 → n5

Explanation: The transition of an electron from n3 to n2 in the hydrogen atom emits the maximum energy because the energy levels are closer together…

• A. A
• B. B
• C. C
• D. D

Explanation: The correct answer is A. The ultraviolet (UV) region is a part of the electromagnetic spectrum that is positioned between the visible…

• A. 1s
• B. 2p
• C. 3s
• D. 3d

Explanation: In atomic physics, photon emission occurs when an electron transitions from a higher energy level to a lower one.

• A. 3.5 atm
• B. 1 atm
• C. 3 atm
• D. 1.25 atm
• E. 2.25 atm

Explanation: 1 atm -> 760 torr X atm ->950 torr X=1.25 atm

• A. 400 torr
• B. 50662 Pa
• C. 101.3 Pa
• D. 8.5 pounds

Explanation: Atmospheric pressure on sea level is 101,325 Pa/760 torr/14.7 pounds per inch.

• A. 1.050
• B. 10.38
• C. 1.380
• D. 2.760

Explanation: The torr is a unit of pressure defined as exactly 1/760 of a standard atmosphere.

• A. 350 K
• B. 343 K
• C. 300 K
• D. 283 K

Explanation: To convert temperature from celsius to kelvin scale the formula is °C + 273.15 K 70° + 273.15 =343 K.

• A. 754 torr
• B. 54.6 mm of water
• C. 1.01 atm
• D. 74.0 cm Hg

Explanation: 1 inch of Hg = 2.54 cm of Hg 30.2 inches of Hg = 30.2 (2.54) cm of Hg = 30.2 (5.08/2) = 15.1(5.08) = 76.7 cm of Hg = 767 torr 760 torr = 1…

• A. Nm-2
• B. Nm2
• C. mm of Hg
• D. atm

Explanation: Pressure:Pressure is defined as force per unit area. P = F/ A---> P = N/m^2---> P = Nm^-2 Hence, A is the correct option.

• A. 76cm
• B. 76mm
• C. 76dm
• D. 76pm

Explanation: At sea level, the atmosphere exerts a pressure of 760mm Hg. This is used to define another pressure unit called the atmosphere (atm).One…

• A. 16 torr
• B. 159 torr
• C. 158 torr
• D. 157 torr

Explanation: Option B is correct as group level partial pressure effect oxygen is "159 torr". Any less than that causes discomfort in breathing.

• A. 10:1
• B. 1:2
• C. 2:3
• D. 3:2
• E. 2:1

Explanation: No of moles=mass in g/MrMoles of water = 18/18 =1 mol 1mol=24dm3 so volume of water is also 24dm3 Moles of CO2= 4.4/44 = 0.1 moles0.1x24=…