Which of the following statements is correct for the test for carbon dioxide?
It changes limewater from milky to colourless.
It changes limewater from colourless to pink.
It changes limewater from colourless to milky.
Which of the following statements is correct for the test for hydrogen gas?
It relights a glowing splint.
It gives a pop sound with a glowing splint.
It gives a pop sound with a lit splint.
Which of the following statements is correct for the test for oxygen gas?
It relights a burning splint.
It extinguishes a burning splint.
Which gas is used in food packaging?
Carbon dioxide.
Nitrogen.
Oxygen.
Which of the following equations represents the reaction that is used to safely prepare hydrogen gas in the laboratory?
Zn + 2HCl -> ZnCl2 + H2
2Na + 2HCl -> 2NaCl + H2
Cu + 2HCl -> CuCl2 + H2
Which gas is used in medicine and welding?
Burning elements in oxygen can form acidic or basic oxides. Which of the following forms an acidic oxide?
Carbon.
Magnesium.
Copper.
Which of the following chemicals is used in the test for ammonia gas?
Concentrated nitric acid.
Concentrated hydrochloric acid.
Concentrated sulphuric acid.
The physical properties of carbon dioxide are:
Colourless, odourless and less dense than air.
Colourless, odourless and denser than air.
Clear, odourless and less dense than air.
The catalyst used in the preparation of oxygen gas is:
Manganese(IV) oxide.
Magnesium oxide.
Magnesium(IV) oxide.