Download App

Study of the First Element - Hydrogen — CHEMISTRY STD 9 — Question

ICSE BoardEnglish MediumSTD 9CHEMISTRYStudy of the First Element - Hydrogen5 Marks
Question
When hydrogen is passed over a black solid compound A, the products are a 'colorless liquid' and a 'reddish-brown metal B'.
Substance B is divided into two parts each placed in separate test tubes.
Dilute HCl is added to one part of substance B and dilute $HNO_3$ to the other.
  1. Name the substances A and B.
  2. Give two tests for the colourless liquid formed in the experiment.
  3. What happens to substance A when it reacts with hydrogen? Give reasons for your answer.
  4. Write an equation for the reaction between hydrogen and substance A.
  5. Is there any reaction between substance B and dilute hydrochloric acid? Give reasons for your answer.
✓

Answer

a. $\mathrm{A}=\mathrm{CuO}, \mathrm{B}=\mathrm{Cu}$
b. Blue and red litmus paper, when dipped in the colourless liquid, do not change colour. This confirms the liquid formed is neutral and is water. It changes white anhydrous copper sulphate to blue salt.
c. Black copper oxide (A) on heating with hydrogen reduces copper oxide to reddish-brown copper and itself gets oxidised to water. Hydrogen is a strong reducing agent and removes oxygen from less active metals, i.e. it removes oxygen from heated metal oxides when passed over them and itself gets oxidised to water.
d. $\mathrm{CuO}+\mathrm{H}_2 \xrightarrow{\Delta} \mathrm{Cu}+\mathrm{H}_2 \mathrm{O}$
e.$\mathrm{Cu}+\mathrm{HCl} \rightarrow$ No reaction
Copper is less reactive than hydrogen and hence cannot displace it from $\mathrm{HCl}$.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "[5 Mark Question Answer]" from Study of the First Element - Hydrogen→Study of the First Element - Hydrogen — all question types→CHEMISTRY STD 9 question papers→ICSE Board STD 9 question papers→ICSE Board question paper generator→

Similar questions

 $800 cm^3$ of gas is collected at 650 mm pressure. At what pressure would the volume of the gas reduce by $40 \%$ of its original volume, the temperature remaining constant?
→
What do you understand by the following terms?
→
How does the Modern atomic theory contradict and correlate with Dalton's atomic theory?
→
Why are anode rays also called as 'canal rays'?
→
How can you say these are chemical changes? Give one reason for your answer.
→
How can these impurities be removed?
→
What are cathode rays? How are these rays formed?
→
Draw diagrams representing the atomic structures of the following:
  1. Sodium atom
  2. Chlorine ion
  3. Carbon atom
  4. Oxygen ion
→
Match the following:
Compound Formula
1. Boric acid i. $NaOH$
2. Phosphoric acid ii. $SiO_2$
3. Nitrous acid iii. $Na_2CO_3$
4. Nitric acid iv. $KOH$
5. Sulphurous acid v. $CaCO_3$
6. Sulphuric acid vi. $NaHCO_3$
7. Hydrochloric acid vii. $H_2S$
8. Silica (sand) viii. $H_2O$
9. Caustic soda (sodium hydroxide) ix. $PH_3$
10. Caustic potash (potassium hydroxide) x. $CH_4$
11. Washing soda (sodium carbonate) xi. $NH_3$
12. Baking soda (sodium bicarbonate) xii. $HCl$
13. Lime stone (calcium carbonate) xiii. $H_2SO_3$
14. Water xiv. $HNO_3$
15. Hydrogen sulphide xv. $HNO_2$
16. Ammonia xvi. $H_3BO_3$
17. Phosphine xvii. $H_3PO_4$
18. Methane xviii. $H_2SO_4$
→
Define exothermic and endothermic changes. Give two example in each case.
→