Water gas is a mixture of :
- A.CO₂ and H₂
- B.CO and H₂
- C.CO₂ and H₂O
- D.CO and H₂O
Correct answer
Explanation
The correct answer is B, CO and H₂. Water gas is made by passing steam over red-hot coke, and the reaction C + H₂O → CO + H₂ gives carbon monoxide and hydrogen in roughly equal volumes. Both of its components burn, so water gas is a useful industrial fuel with a high calorific value. It is also called syngas or synthesis gas, because the same mixture of CO and H₂ is used to make methanol and other chemicals, and it is a source of hydrogen for the Haber process. Producer gas, a related fuel, is a mixture of carbon monoxide and nitrogen made by passing air over hot coke. Option A is wrong because carbon dioxide does not burn and is not the main product of the steam and coke reaction. Option C is wrong because carbon dioxide and steam are both non-combustible, so their mixture cannot be a fuel gas. Option D is wrong because steam is the reactant that is used up, not a part of the product gas. Exam tip: water gas = CO + H₂; producer gas = CO + N₂; coal gas = H₂ + CH₄ + CO.
Practice Questions
View allWhich one of the following is not used as fertilizer?
- A.Ammonium nitrate
- B.Ammonium sulphide
- C.Ammonium phosphate
- D.Ammonium sulphate
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Ammonium sulphide is an unstable, foul-smelling compound that breaks down to release ammonia and toxic hydrogen sulphide, so it is not used as a fertiliser.
Read the full explanation →The focal length of the objective lens of a telescope is 50 cm. If the magnification of the telescope is 25, then the focal length of the eye-piece is
- A.12.5 cm
- B.5 cm
- C.2 cm
- D.10 cm
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For an astronomical telescope in normal adjustment the magnifying power equals the focal length of the objective divided by that of the eyepiece, so the eyepiece focal length is 50 ÷ 25 = 2 cm.
Read the full explanation →The major source of vitamins and minerals for vegetarians is
- A.black gram and wheat.
- B.rice and mustard.
- C.vegetables and fruits.
- D.soya bean and milk.
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Vegetables and fruits supply most of the vitamins and minerals in a vegetarian diet, which is why they are called protective foods.
Read the full explanation →Which one of the following compounds is used in black and white photography?
- A.AgF
- B.AgBr
- C.AgCl
- D.Ag2SO4
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Silver bromide is the light-sensitive compound coated on black and white photographic film and paper, because light breaks it down into tiny grains of silver metal.
Read the full explanation →Which one of the following statements about speed and velocity is correct?
- A.Speed and velocity both are vector quantities.
- B.Speed and velocity both are scalar quantities.
- C.Speed is vector quantity and velocity is scalar quantity.
- D.Speed is scalar quantity and velocity is vector quantity.
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Speed tells only how fast a body moves, while velocity also tells the direction of motion, and a quantity with both magnitude and direction is a vector.
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