The oxidation state of oxygen is zero in

• CO

• O₃

• SO₂

• H₂O₂

Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionisation enthalpy? 

• Vanadium (Z = 23)

• Manganese (Z = 25)

• Chromium (Z= 24)

• Iron (Z = 26)

Which one of the following is an example of non-typical transition elements?

• Li, K, Na

• Be, Al, Pb

• Zn, Cd, Hg

• Ba, Ca, Sr

E°= -0.44V for the reaction, Fe²⁺ + 2e^- → Fe and E°= -0.76 V for the reaction, Zn²⁺ + 2e^- → Zn. Which of the following statement is correct?

• Fe is more electropositive

• Zn is more electropositive

• Zn is more electronegative

• None of the above

Which element from group V gives most basic compound with hydrogen?

• Nitrogen

• Bismuth

• Arsenic

• Phosphorus

Which ion is colourless?

• Cr⁴⁺

• Sc³⁺

• Ti³⁺

• V⁴⁺

Which of the following properties increases on going down from F to I in group VII-A of the periodic table?

• Electronegativity

• Volatile nature

• Ionic radius

• Oxidising power

Which of the following statement is not correct?

• La(OH)₃ is less basic than Lu(OH)₃.

• In lanthanide series ionic radius of Lu³⁺ ion decreases.

• La is actually an element of transition series rather lanthanide.

• Atomic radius of Zr and Hf are same because of lanthanide contraction.

Point out in which of the following properties oxygen differs from the rest of the members of its family (Group-VIA)?

• High value of ionisation energies

• Oxidation states (2,4,6)

• Polymorphism

• Formation of hydrides

The d-block elements consists mostly of

• mono-valent metals

• all non-metals

• elements which generally form stoichiometric metal oxide

• many metals with catalytic properties