Chemistry
Define:
(a) catalytic hydrogenation
(b) oxidation
(c) reduction
(d) redox reaction
(e) electrolysis
(f) electrolyte
Answer
(a) Catalytic hydrogenation is a process by which hydrogen gas is passed through vegetable oils in the presence of a catalyst like Ni, Pt or Pd to convert the oils into vanaspati ghee.
(b) Oxidation is a chemical process that involves addition of oxygen to a substance or removal of hydrogen from a substance.
(c) Reduction is a chemical process that involves addition of hydrogen to a substance or removal of oxygen from a substance.
(d) Redox reactions are those in which reduction and oxidation both take place simultaneously i.e., one substance is reduced while the other gets oxidized.
(e) Electrolysis is a process in which an electric current is passed through an aqueous solution or a molten state of a compound to bring about a chemical change.
(f) Electrolytes are the compounds that in aqueous or molten state that conduct electric current through them because they contain free and mobile ions.
Related Questions
Give examples :
(a) Two metals which give hydrogen with cold water.
(b) A metal which liberates hydrogen only when steam is passed over red hot metal.
(c) A metallic oxide which can be reduced into metal by hydrogen.
(d) An electrolyte.
(e) A metal of which an electrode is made.
Complete and balance the following equations:
(a) H2 + ……………….. ⟶ 2HCl
(b) H2 + S ⟶ ……………………
(c) Zn + ……………. ⟶ ZnCl2 + H2
(d) CuO + ………….. ⟶ Cu + ………….
(e) Fe + H2O ⟶ …………….. + ……………
(f) K + H2O ⟶ ……………… + ……………
How would you show that hydrogen gas is neutral in nature ?
Give reasons for the following:
(a) Hydrogen can be used as a fuel.
(b) Though hydrogen is lighter than air it cannot be collected by downward displacement of air.
(c) A pop sound is produced when hydrogen gas is burnt.
(d) Helium has replaced hydrogen in weather observation balloons.
(e) Nitric acid is not used for the preparation of hydrogen gas.