All Free Chemistry MCQs with Answers

• A. A: Low potential and low pressure
• B. B: Low potential and high pressure
• C. C: High potential and high pressure
• D. D: High potential and low pressure

Explanation: In a discharge tube, cathode rays are produced when electrons are emitted from the cathode and accelerated towards the anode.

• A. JJ Thomson
• B. E Rutherford
• C. R Milliken
• D. WC Roentgen

Explanation: The determination of the charge of the electron using the effect of an electric field on the rate of fall of oil droplets under gravity…

• A. Quantized
• B. Integral multiple of 'e'
• C. Not less than 'e'
• D. All of the above

Explanation: Millikan's oil drop experiment demonstrated that the charge on an oil droplet is quantized, meaning it can only exist in discrete values…

• A. Any atomic nucleus
• B. A radioactive atomic nucleus
• C. A neutron or a proton
• D. A neutron proton or an electron

Explanation: A nucleon is either a proton or a neutron, which are the subatomic particles found in the nucleus of an atom.

• A. -OH
• B. -NH2
• C. -SO2H
• D. -COOH

Explanation: Amines are used in making azo dyes and nylon apart from medicines and drugs.

• A. Ferromagnetic
• B. Diagmagnetic
• C. Electromagnetic
• D. Paramagnetic

Explanation: A ferromagnetic substance, like iron, retains magnetic properties after removing the field.

• A. Mg
• B. He
• C. Fe
• D. Ne

Explanation: Isoelectronic species have the same number of electrons. In this case, Na+ has 10 electrons after losing one to become an ion.

• A. Ar & Cl-
• B. Ca & Ar
• C. Mg and Na
• D. Ag & Sn

Explanation: Argon has 18 electrons. The chloride ion also has 18 electrons.

• A. 37
• B. 32
• C. 35
• D. 20

Explanation: Atom A has 18 electrons with net charge of -1 which means it gained one electron.

• A. Ar & Cl-1
• B. Ca & Ar
• C. Mg & Na
• D. Ag & Sn

Explanation: Ar = 1s22s22p63s23p6 Cl- = 1s22s22p63s23p6 (doing for 18 electron instead of 17 because it gained one electron/anion)

• A. Charge number
• B. Mass number
• C. Atomic number
• D. Magic number

Explanation: Mass number is the sum of protons and neutrons in the nucleus.

• A. 3d10 4s1
• B. 3d11 4s0
• C. 3d10 4s2
• D. 3d10 4s0

Explanation: The electronic configuration of copper (Cu) is obtained by filling the orbitals in order of increasing energy.

• A. diamagnetic
• B. paramagnetic
• C. ferromagnetic
• D. electromagnetic

Explanation: Those substances which have at least only one unpaired electron are called diamagnetic substances.

• A. The number of electrons in the outermost shell
• B. The number of electrons that are easily ejected
• C. The number of unpaired electrons
• D. The number of lone pair electrons

Explanation: A paramagnetic substance is one that is weakly attracted by a magnetic field due to the presence of unpaired electrons in its atoms or…

• A. N
• B. P-³
• C. K+
• D. F-

Explanation: O2-, F-, Na+ and Mg2+ are known as isoelectronic species as they all have the same no. of electrons(10).

• A. Hund's rule
• B. Aulban rule
• C. Paoli's exclusion lrinciple
• D. Thumb rule

Explanation: Hund's Rule: Hund's rule is a principle in quantum mechanics that states that for a given electron shell, orbitals of equal energy are…

• A. Protons
• B. Neutrons
• C. Electrons
• D. All of above

Explanation: Electrons (especially valence electrons) are only subatomic particles which are involved in ordinary chemical changes

• A. Proton
• B. Electron
• C. Neutrons
• D. None of above

Explanation: Therefore, the correct option is "None of the above" as H+ ion and helium atom have different numbers of protons, electrons, and neutrons.

• A. Diamagnetic
• B. Paramagnetic
• C. Ferromagnetic
• D. Anti Ferromagnetic

Explanation: Paramagnetic: Oxygen molecules (O2) are paramagnetic. Paramagnetic substances have unpaired electrons, which generate a net magnetic…

• A. Coulomb potential
• B. Vapor pressure
• C. Electronic configuration
• D. Entropy

Explanation: The Aruba principle, also known as the Aufbau principle, governs the filling order of atomic orbitals in an atom's electronic…