10 th Science quiz

What is the valency of hydroxide ion

• -1

• +1

• -2

• +2

Formation of Water molecule from Hydrogen and Oxygen is a which type of reaction?

• Displacement

• Double displacement

• Combination

• Decomposition

Which of the following is not chemical change?

• Boiling of water

• Melting of ice

• Dissolution of salt into water

• Combustion of LPG

The following reaction is an example of

4 NH₃ + 5 O₂ → 4 NO + 6 H₂O

• Displacement reaction

• combination reaction

• Double displacement reaction

• Decomposition reaction

which of the following is exothermic reaction?

• Evaporation of water

• Dilution of acid

• Sublimation of camphore

• Decomposition of chlorine

which of the following gases can be used for storage of fresh sample of an oil for a long time?

• Carbon dioxide and oxygen

• Nitrogen and oxygen

• Carbon dioxide and Helium

• Helium and Nitrogen.

Which of the following reaction involve chemical reactions?

• Storing of oxygen gas under pressure in a gas cylinder.

• Liquefaction of air

• Keeping petrol in a china dish in open

• Heating of copper wire

Oxidation Means

• Gain of hydrogen

• Loss of oxygen

• Addition of Oxygen

• Loss of electron

Which of the following is formula of caustic soda

• NaOH

• NaCl

• CaOCl₂

• NaHCO₃

Which of the following is formula of Bleaching powder

• NaOH

• NaCl

• CaOCl₂

• NaHCO₃