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Explain why? (a) Common salt becomes sticky during the rainy season
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2
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5932
|
December 21, 2020
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With the help of a chemical equation, explain how a soda-acid fire extinguisher helps in putting out a fire
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1
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13479
|
August 5, 2019
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1. Why does an aqueous solution of acid conduct electricity?
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1
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28113
|
March 29, 2019
|
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A student prepared solutions of (z) an acid and (ii) a base in two separate beakers
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1
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861
|
March 29, 2019
|
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Name the gas that liberates when an acid reacts with a metal. Illustrate your answer
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1
|
609
|
March 29, 2019
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How is Plaster of Paris chemically different from gypsum? How may these be inter converted? Write one use of Plaster of Paris
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1
|
1810
|
March 29, 2019
|
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What is ‘Plaster of Paris’ chemically? How is it obtained from gypsum? Write the condition and chemical equation involved in its manufacture?
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1
|
2585
|
March 29, 2019
|
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1. Write the chemical name and formula of bleaching powder
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1
|
2108
|
March 29, 2019
|
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1. Write the formula and chemical name of bleaching powder
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1
|
2393
|
March 29, 2019
|
|
(a) What is the action on litmus of: (i) Dry ammonia gas. (ii) Solution of ammonia gas in water
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1
|
8455
|
March 29, 2019
|
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(a) What is meant by pH of a solution? (b) State one difference between a strong electrolyte and a weak electrolyte. Give one example of each
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1
|
773
|
March 29, 2019
|
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How did Arrhenius define acids and bases? Choose a strong acid and a weak base from the following substances:
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1
|
690
|
March 29, 2019
|
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Identify the compound of calcium which is used for plastering of fractured bones with the help of chemical equation, describe how this compound is prepared
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1
|
4735
|
March 29, 2019
|
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Identify the compound of calcium which is yellowish white powder and is used for disinfecting drinking water. How is it manufactured?
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1
|
1915
|
March 29, 2019
|
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A compound X of sodium forms a white powder. It is a constituent of baking powder and is used in some antacid prescriptions
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1
|
16698
|
March 29, 2019
|
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Write the chemical name and formula of washing soda. What happens when ciystals of washing soda are exposed to air?
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1
|
4521
|
March 29, 2019
|
|
A compound X of sodium is commonly used in kitchen for making crispy pakoras. It is also used for curing acidity in the stomach. Identify 'X'
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1
|
1179
|
March 29, 2019
|
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State the chemical property in each case on which the following uses of baking soda are based: (i) As an antacid (ii) As a constituent of baking powder
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1
|
8111
|
March 29, 2019
|
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A dry pellet of a common base B, when kept in open absorbs moisture and turns sticky
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1
|
2120
|
March 29, 2019
|
|
While constructing a house, a builder selects marble flooring and marble table top for the kitchen where vinegar and juices of lemon tamarind etc
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1
|
5747
|
March 29, 2019
|
|
A student heated a few crystals of copper sulphate in a dry boiling tube. (a) What will be the colour of the copper sulphate after heating?
|
|
1
|
2420
|
March 29, 2019
|
|
A knife, which is used to cut a fruit, was immediately dipped into water containing drop of blue litmus solution
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1
|
968
|
March 29, 2019
|
|
You might have seen lemon or tamarind juice being used to clean tranished surface of copper vessels. Explain why these sour substances are effective in cleaning the vessels
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1
|
785
|
March 29, 2019
|
|
Write the name and chemical formula of the calcium compound used for disinfecting drinking water. How is this compound manufactured?
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|
1
|
3245
|
March 29, 2019
|
|
Which one of these has a higher concentration of H+ ions? 1M HC1 or 1M CH3COOH
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|
1
|
3755
|
March 29, 2019
|
|
Why does 1M HCL Solution have a higher concentration of H+ ions than 1M CH3COOH solution?
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1
|
5841
|
March 29, 2019
|
|
What effect does an increase in concentration of H+(aq) in a solution have on the pH of solution?
|
|
1
|
2413
|
March 29, 2019
|
|
Salt A commonly used in bakery products on heating gets converted into another salt B which itself is used for removal of hardness of water and a gas C is evolved
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|
1
|
1038
|
March 29, 2019
|
|
A yellow powder X gives a pungent smell if left open in air. It is prepared by the reaction of dry compound Y with chlorine gas
|
|
1
|
5057
|
March 29, 2019
|
|
Bleaching powder forms a milky solution in water. Explain
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|
1
|
2486
|
March 29, 2019
|
