ISCE Worksheet for chapter-7 Halogen class 9

Worksheet For class 9

Find ICSE Worksheet for chapter-9 Halogen class 9

CLASS-9

BOARD: ICSE

Chemistry Worksheet - 9

TOPIC: HYDROGEN

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HYDROGEN

SUMMARY –

• Position in the periodic table.
• Similarity with alkali metals and halogen.
• Discovery, occurrence, general methods of preparation, laboratory method (by action of dil. Acid on zinc), Industrial method (Bosch process, electrolysis of water or brine, from natural gas, from CaH₂).
• Tests and uses.

SECTION -1

1. Write two equations which suggest that hydrogen is a reducing agent.
2. Choose the words from the options given in the brackets to complete these sentences.
   1. When CuO reacts with hydrogen,_________ is reduced and is oxidized to (CuO, H₂, Cu, H₂O).
   2. Hydrogen is soluble in water. (sparingly, highly, moderately).
   3. Sodium reacts smoothly with cold water. (metal, amalgam, in the molten state)
   4. Metals like , and give H₂ with steam.
   (iron, magnesium, aluminium, sodium, calcium)
   5. A metal____________ hydrogen in the activity series gives hydrogen with________
   acid or acid. (above, below, hydrochloric, nitric acid , dilute sulphuric)
3. Give reasons :
   1. Why hydrogen is collected by the downward displacement of water and not by air, even though it is lighter than air.
   2. A candle when brought near the mouth of the jar containing hydrogen gas starts burning but the candle is extinguished when pushed into the jar.
   3. An oxy-hydrogen flame is used for welding and cutting metals.
   4. Apparatus for the laboratory preparation of hydrogen should be air tight and away from a naked flame.

SECTION – 2

1. How does hydrogen occur in nature ?
2. Which test should be made before collecting hydrogen in a glass jar ?
3. In which respect hydrogen differs from –
   1. Alkali metals.
   2. Halogen.
4. How will you prepare hydrogen gas in laboratory ? State three precautions necessary for the collection of hydrogen.
5. How is hydrogen prepared industrially by Bosch process ?
6. Without burning hydrogen, how can you prove that its product of oxidation is water ?
7. Give important uses of hydrogen.