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Chemistry Past Questions and Answers

Chemistry Questions

Question 456:
Which of the following sulphides is insoluble in dilute HCl?
  • A Na<sub style='font-size: smaller;'>2</sub>S
  • B ZnS
  • C CuS
  • D FeS
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Question 457:
When chlorine is passed into water and subsequently exposed to sunlight, the gas evolved is?
  • A HCl
  • B HOCl
  • C O<sub style='font-size: smaller;'>2</sub>
  • D Cl<sub style='font-size: smaller;'>2</sub>O
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Question 458:
A substance Z reacts with NaOH to give salt and water only. When Z is treated with dilute HCl, a gas is evolved which gives a yellow suspension on passing into concentrated H<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>4</sub>. Substance Z is?
  • A NaHS
  • B Na<sub style='font-size: smaller;'>2</sub>SO<sub style='font-size: smaller;'>3</sub>
  • C Na<sub style='font-size: smaller;'>2</sub>S
  • D NaHSO<sub style='font-size: smaller;'>3</sub>
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Question 459:
Ammonia gas is normally dried with?
  • A Concentrated sulphuric acid
  • B Quicklime
  • C Anhydrous calcium chloride
  • D Magnesium sulphate
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Question 460:
What are the values of x, y and z respectively in the equation: xCu + yHNO<sub style='font-size: smaller;'>3</sub> → xCu(NO<sub style='font-size: smaller;'>3</sub>)<sub style='font-size: smaller;'>2</sub> + 4H<sub style='font-size: smaller;'>2</sub>O + zNO?
  • A 4: 1: 2
  • B 3:8:2
  • C 2:8:3
  • D 8:3:2
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