Chemistry
Choose terms from the options given in brackets to complete these sentences.
(a) When CuO reacts with hydrogen, …………… is reduced to …………… and …………… is oxidized to …………… . (CuO, H2, Cu, H2O)
(b) Hydrogen is …………… soluble in water. (sparingly, highly, moderately)
(c) Metals like ……………, …………… and …………… give H2 with steam. (iron, magnesium, aluminium, sodium, calcium)
(d) Sodium …………… reacts smoothly with cold water. (metal, amalgam, in the molten state)
(e) A metal …………… hydrogen in the activity series gives hydrogen with …………… acid or …………… acid. (above, below, dilute hydrochloric, concentrated hydrochloric, dilute sulphuric).
Answer
(a) When CuO reacts with hydrogen, CuO is reduced to Cu and H2 is oxidized to H2O
(b) Hydrogen is sparingly soluble in water.
(c) Metals like magnesium, iron and aluminium give H2 with steam.
(d) Sodium amalgam reacts smoothly with cold water.
(e) A metal above hydrogen in the activity series gives hydrogen with dilute hydrochloric acid or dilute sulphuric acid acid.
Related Questions
Assertion (A): Zinc is preferred for the laboratory preparation of hydrogen.
Reason (R): Zinc is unique in nature and does not contain any impurity.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Assertion (A): Reduction is defined as the process of removal of oxygen from a substance or the addition of hydrogen to a substance.
Reason (R): Hydrogen is a reducing as well as an oxidising agent.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false.
- A is false but R is true.
Name
(a) an oxidizing agent that does not contain oxygen.
(b) a substance that oxidizes concentrated HCl to chlorine.
(c) a substance that will reduce aqueous Iron (III) ions to Iron (II) ions.
(d) a liquid that is an oxidizing as well as a reducing agent.
(e) a gas that is an oxidizing as well as a reducing agent.
(f) a solid that is an oxidizing agent.
Correct the following statements:
(a) Hydrogen is separated from CO by passing the mixture through caustic potash solution.
(b) All metals react with acids to give hydrogen.
(c) Hydrogen is dried by passing it through conc. H2SO4.
(d) Very dilute nitric acid reacts with iron to produce hydrogen.
(e) Conc. H2SO4 reacts with zinc to liberate hydrogen.