Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions

Which of the following is not an example of redox reaction?

Identify disproportionation reaction

Which of the following elements does not show disproportionation tendency?

Which of the following statement(s) is/are not true about the following decomposition reaction.

\[\ce{2KClO3 -> 2KCl + 3O2}\]

(i) Potassium is undergoing oxidation.

(ii) Chlorine is undergoing oxidation.

(iii) Oxygen is reduced.

(iv) None of the species are undergoing oxidation or reduction.

Identify the correct statements with reference to the given reaction.

\[\ce{P4 + 3OH- + 3H2O -> PH3 + 3H2PO^{-}2}\]

(i) Phosphorus is undergoing reduction only.

(ii) Phosphorus is undergoing oxidation only.

(iii) Phosphorus is undergoing oxidation as well as reduction.

(iv) Hydrogen is undergoing neither oxidation nor reduction.

\[\ce{MnO^{2-}4}\] undergoes disproportionation reaction in acidic medium but \[\ce{MnO^{-}4}\] does not. Give reason.

Assertion (A): The decomposition of hydrogen peroxide to form water and oxygen is an example of disproportionation reaction.

Reason (R): The oxygen of peroxide is in –1 oxidation state and it is converted to zero oxidation state in \[\ce{O2}\] and –2 oxidation state in \[\ce{H2O}\].

Assertion (A): Redox couple is the combination of oxidised and reduced form of a substance involved in an oxidation or reduction half cell.

Reason (R): In the representation \[\ce{E^Θ_{Fe^{3+}/Fe^{2+}}}\] and \[\ce{E^Θ_{Cu^{2+}/Cu}, Fe^{3+}/Fe^{2+}}\] and \[\ce{Cu^{2+}/Cu}\] are redox couples.

Why does fluorine not show disporportionation reaction?

Write redox couples involved in the reactions given.

\[\ce{Cu + Zn^{2+} ->Cu^{2+} + Zn}\]

Write redox couples involved in the reactions given.

\[\ce{Mg + Fe^{2+} -> Mg^{2+} + Fe}\]

Write redox couples involved in the reactions given.

\[\ce{Br2 + 2Cl- -> Cl2 + 2Br-}\]

Write redox couples involved in the reactions given.

\[\ce{Fe + Cd^{2+} -> Cd + Fe^{2+}}\]

Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine.

\[\ce{NaClO4, NaClO3, NaClO, KClO2, Cl2O7, ClO3, Cl2O, NaCl, Cl2 , ClO2}\].

Which oxidation state is not present in any of the above compounds?

Which of the following hydrides is electron-precise hydride?

Which of the following statements about hydrogen are correct?

(i) Hydrogen has three isotopes of which protium is the most common.

(ii) Hydrogen never acts as cation in ionic salts.

(iii) Hydrogen ion, \[\ce{H+}\], exists freely in solution.

(iv) Dihydrogen does not act as a reducing agent.

Which of the following statements is correct?

(i) Elements of group 15 form electron deficient hydrides.

(ii) All elements of group 14 form electron precise hydrides.

(iii) Electron precise hydrides have tetrahedral geometries.

(iv) Electron rich hydrides can act as Lewis acids.

Explain the following:

Gallium has higher ionisation enthalpy than aluminium.

Explain the following:

Aluminium forms [AlF₆]^3– ion but boron does not form [BF₆]^3– ion.

Assertion (A): If aluminium atoms replace a few silicon atoms in three-dimensional network of silicon dioxide, the overall structure acquires a negative charge.

Reason (R): Aluminium is trivalent while silicon is tetravalent.