CSCE TUTORIAL
Acid, Bases and Salt
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What colour do the following indicators turn when added to a base or alkali (such as sodium hydroxide)?
(a) Methyl orange (b) litmus (c) red cabbage extract
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What will be the action of the following substances on litmus paper?
a. Dry HCI gas
b. Moistened NH3 gas
c. Lemon juice
d. Carbonated soft drinks
e. Curd
f. Soap solution
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Name the acid present in ant sting and give its chemical formula. Also, give the common method to get relief from the discomfort caused by the ant sting.
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Name an indicator which is pink in an alkaline solution but turns colourless in an acidic solution.
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When a solution is added to a cloth strip treated with onion extract, then the smell of onion cannot be detected. State whether the given solution contains an acid or base.
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How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal?
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Name the gas that evolved when dilute HCl reacts with sodium hydrogen carbonate. How is it recognized?
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(a) Write the chemical name and formula of marble.
(b) It has been found that marbles of Taj are getting corroded due to development of industrial areas around it. Explain this fact giving a chemical equation.
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How would you distinguish between baking powder and washing soda by heating?
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Salt A is commonly used in bakery products on heating gets converted into another salt B, which is used to remove the hardness of water, and a gas C is evolved. The gas C, when passed through lime water, turns it milky. Identify A, B and C.
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In one of the industrial processes used to manufacture sodium hydroxide, a gas X is formed as a byproduct. The gas X reacts with lime water to give a compound Y used as a bleaching agent in the chemical industry. Identify X and Y giving the chemical equation of the reactions involved.
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When zinc metal is treated with a dilute solution of a strong acid, a gas is evolved, which is utilised in the hydrogenation of oil. Name the gas evolved. Write the chemical equation of the reaction involved and also write a test to detect the gas formed.
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For making cake, baking powder is taken. If your mother uses baking soda instead of baking powder in cake at home,
(a ) How will it affect the taste of the cake and why?
(b ) How can baking soda be converted into baking powder?
(c ) What is the role of tartaric acid added to baking soda?
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A metal carbonate X reacting with acid gives a gas that gives the carbonate back when passed through a solution Y. On the other hand, a gas G obtained at the anode during electrolysis of brine is passed on dry Y, it gives a compound Z, used for disinfecting drinking water. Identity X, Y, G and Z.
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Name on natural source of each of the following acids:
(a) Citric acid (b) Oxalic acid (c) Lactic acid (d) Tartaric acid
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Fresh milk has a pH will change as it turns into curd? Explain.
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A milkman adds a very small amount of baking soda to fresh milk.
(i) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(ii) What do you expect to observe when milk comes to boil?
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What happens when sodium carbonate reacts with dilute HCl acid?
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Why are metallic oxides called basic oxides?
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State the number of water molecules present in crystals of washing soda and plaster of paris. What are these water molecules called as?
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A white powder is used by doctor to support fractured bones write the chemical name of it. Write the chemical equation of its preparation. Why should it be stored in a dry place? Give one more use of the white powder.
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State the chemical property in each case on which of the following uses of baking soda are based :
a. as an antacid
b. as a constituent of baking powder
