All Free Chemistry MCQs with Answers

• A. Option A
• B. Option B
• C. Option C
• D. Option D

Explanation: a) Titanium (Ti): Titanium commonly exhibits oxidation states of +2 and +4.

• A. Alkali metals
• B. Transition elements
• C. Alkaline earth metal
• D. Element which form border line compound

Explanation: Correct option: Based on the information provided, the correct option for elements used as catalysts in chemical reactions is: B)…

• A. +1, +2
• B. +2, +3
• C. +4, +5
• D. +6, +7

Explanation: Based on the typical behavior of elements in the 3d-series of the periodic table, the correct option for stable oxidation states is…

• A. [Co(NH3 )4 (H2 O)Br](NO3 )2 .
• B. [Co(NH3 ) (H2 O)Br](NO3 )2 .
• C. Co[Br(H2O)(NH3)4](NO3)2
• D. Co[(NO)(NH3)4(H2O)Br](NO3)2

Explanation: Central metal ion: The central metal is cobalt (Co), and its oxidation state is +3(indicated by "III").Ligands:NH3 (ammine) is a neutral…

• A. 1s2 2s2 2p6, 3s2 3p6 3d3
• B. 1s2 2s2 2p6 3s2 3p6 4s2 4p1
• C. 1s2 2s2 2p6 3s2 3p6 3d1 4s2
• D. 1s22s22p63s23p64s64p2

Explanation: The correct electronic configuration for scandium (atomic number 21) is Option C) 1s^2 2s^2 2p^6 3s^2 3p^6 3d^1 4s^2.

• A. They are all metals in true sense
• B. They show variable oxidation state
• C. They have high melting and boiling points
• D. Their ionization energy is less than that of IIA group elements

Explanation: The ionization energy of an atom is the energy required to remove an electron from the atom.

• A. It decreases continuously
• B. First it decreases then increases rapidly
• C. First it decreases in the start, constant in the middle and then increases at the end of series
• D. It remains almost constant in the series

Explanation: The covalent radii of transition elements generally follow this trend. As you move from left to right across the 3D series of transition…

• A. IIB and IIIB
• B. IVB and VB
• C. VB and VIB
• D. VIB and VIIB

Explanation: In moving from left to right in any transition series, the number of unpaired electrons increases up to groups VB and VIB, after that…

• A. H
• B. B
• C. N
• D. Br

Explanation: While bromine can form compounds with various elements, it is not typically associated with entering interstices of transition metals to…

• A. Binding energy depends on unpaired electrons
• B. M.P and B.Ps show irregular trend in 3d-series
• C. Diamagnetic substances are weekly repelled by the strong magnetic field
• D. Changes in the ionic radii along the series are regular

Explanation: Changes in the ionic radii along the series are much less regular, so that periodic trends in the properties of these ions are difficult…

• A. Fe+3
• B. Cr+3
• C. Ti+3
• D. Cu+2

Explanation: The paramagnetic behaviour is the strongest for Fe3+ and Mn2+

• A. Cr
• B. Ni
• C. Mn
• D. Ti

Explanation: The correct answer is Titanium (Ti). Titanium's atomic size and bonding characteristics make it less suitable for substitution in…

• A. They have partially filled d orbitals
• B. They show variable oxidation states
• C. Both A and B
• D. They have strong bonding

Explanation: The correct answer is Both A and B. Transition elements form complexes due to their partially filled d orbitals, which can overlap with…

• A. Diamagnetic
• B. Paramagnetic
• C. Good conductor
• D. Ferromagnetic

Explanation: Paramagnetic materials are those that are attracted to a magnetic field.

• A. Fe2+
• B. Mn2+
• C. Cr3+
• D. Zn2+

Explanation: Manganese (II) ion has 5 unpaired electrons in its d-orbital configuration. Its electron configuration is [Ar]3d5.

• A. Variable
• B. Constant
• C. Single
• D. infinite

Explanation: Because their valence electrons are in two separate sets of orbitals, (n-1)d and ns, these elements have varying oxidation states.

• A. Paramagnetic
• B. Diamagnetic
• C. Ferromagnetic
• D. None of these

Explanation: Cu+2 salts are paramagnetic. Paramagnetism is a property exhibited by certain substances that are attracted to an external magnetic field.

• A. Paired electrons
• B. Unpaired electrons
• C. Protons
• D. Neutrons

Explanation: The paramagnetic behavior of an atom, ion, or molecule is due to the presence of unpaired electrons.

• A. Mn
• B. Sc
• C. V
• D. Zn

Explanation: Overall, the combination of strong metallic bonds, an extended network of atoms, and delocalized electrons contributes to vanadium's high…

• A. Increase, decrease
• B. Decrease, increase
• C. Decrease, decrease
• D. Increase, increase

Explanation: Option A is correct as the trend of unpaired electrons in the transition elements increases until manganese (Mn) and then decreases until…