Question

Q.3 Name one each of acidic, basic and neutral substances. Q.4 What are the general properties of an acid and a base?Q.5 What is an indicator? Give examples of two natural indicators?Q.6 What is an acid rain? How is it formed? Mention three bad effects of acid rain.Q.7 Name four substances that can serve as indicators.Q.8 Turmeric indicator does not indicate whether the substance is acidic or neutral. Is thestatement true? Explain.Q.9 What is the color of litmus paper which changes its color in acidic solution?Q.10 If few drops of purple-cabbage juice are added to the colorless solution of an acidicmaterial. What would be the color of the resulting solution?Q.11 A few drops of china rose indicator are added to the colorless solution of a chemicalthe resulting solution will become light green. What does it indicate about the natureof the chemical? Q.12 What is a neutralization reaction? Does a neutralization reaction always result in theformation of neutral salt?Q.13 Write a note on uses of bases.Q.14 You are given three unknown liquids an acid other is a base and third is a neutralsubstance. How will you classify the given liquids as acidic, basic and neutral?Q.15 An acidic material is mixed with an equivalent amount of a basic material.(i) What is the reaction called?(ii) What products are formed?Q.16 Explain why(i) Great care should be taken while handling Laboratory acids and bases.(ii) Acidic soil is treated with a base and basic soil is treated with organic matter.Q.17 How is a salt formed?Q.18 What happens when metals and non-metals combine with Oxygen?Q.19 Nancy a class-VII student was performing an experiment in the Chemistry lab. Herteacher instructed her1) Not to waste/smell chemicals2) Not to dispose off all chemicals in the sink.3) Not to mix chemicals haphazardly for example, never add water to acid todilute it; always add acid slowly to water.Why did the teacher advice Nancy to follow the above safety measures?HOTS QUESTIONSQ.1 If you get Turmeric stain on your clothes while eating food, and try to wash it off withsoap, the stain becomes red. Why? Find out how to remove haldi stains from clothes.Q.2 Is the meaning of weak acid the same as that of dilute acid?Q.3 The waste of many factories contain acids. Why is it considered necessary toneutralize them before allowing the waste to flow into water bodies.?

Answer 1

One acidic, basic and neutral substance- salt, pure water The general properties of an acid and a base- Acids taste sour, bases taste bitter. Acids react with carbonates, bases do not react with carbonates, acids turn blue litmus paper red whereas bases turn red litmus paper blue.

  Indicator is- a substance used to indicate or determine the pH scale of another substance

 Two natural indicators- red cabbage juice, turmeric

 Acid rain- the rain that falls on the ground with harmful chemicals that is present in the air.

 It is formed- by the sulphur dioxide and nitrogen oxide are released into the air and they rise up in the atmosphere to get mixed with other constituents.

Three bad effects of acid rain- Acid rain carry certain chemical particles that when consumed by human or animals can cause severe harm to their functioning. They mostly impact the sea and aquatic life.

  Four substances that can serve as indicators- cabbage, grapes, turmeric, cherries

 Turmeric indicator does not indicate whether the substance is acidic or neutral. Is the statement true- False, turmeric indicator indicates whether the substance is acidic or not, being a natural indicator.

 The colour of litmus paper which changes its colour in acidic solution- blue

Answer 2

Explanation:

3 Name one each of acidic, basic and neutral substances