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ScienceClass 10CBSE

Fill in the missing data in the following table Salted Obtained from Name of the Salt Formula Base Acid Ammonium chloride NH4Cl NH4OH - Copper sulphate - - H2 SO4 Sodium chloride NaCl NaOH - Magnesium nitrate Mg (NO3 ) 2 - HNO3 Potassium sulphate K2 SO4 - - Calcium nitrate Ca(NO3 ) 2 Ca(OH)2 -

Soln: Salted Obtained from Name of the Salt Formula Base Acid Ammonium chloride NH4Cl NH4OH HCl Copper sulphate CuSO4 Cu(OH)2 H2 SO4 Sodium chloride NaCl NaOH HCl Magnesium nitrate Mg (NO3 ) 2 Mg(OH)2 HNO3 Potassium sulphate K2 SO4 KOH H2SO4 Calcium nitrate Ca(NO3 ) 2 Ca(OH)2 HNO3

ScienceClass 10CBSE

What are strong and weak acids? In the following list of acids, separate strong acids from weak acids. Hydrochloric acid, citric acid, acetic acid, nitric acid, formic acid, sulphuric acid.

Strong acids are those which gets completely ionized and weak acids are those which gets partially ionized. Hydrochloric acid- Strong Acid citric acid- Weak Acid acetic acid- Weak Acid nitric acid, - Strong Acid formic acid- Weak Acid sulphuric acid- Strong Acid

ScienceClass 10CBSE

In one of the industrial processes used for manufacture of sodium hydroxide, a gas X is formed as by product. The gas X reacts with lime water to give a compound Y which is used as a bleaching agent in chemical industry. Identify X and Y giving the chemical equation of the reactions involved.

Soln: X = Chlorine (Cl 2) Y = Bleaching powder (CaOCl2) Ca(OH)2 (s) + Cl2 (g) → CaOCl2 (s) + H2O — Calcium oxychloride (bleaching powder)

ScienceClass 10CBSE

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. The gas C when passed through lime water, turns it milky. Identify A, B and C.

Soln: Salt A is Baking soda (Sodium Hydrogen Carbonate) which will turn to Sodium carbonate( Salt B) on heating. Gas C turn lime water milky hence it must be CO2.

ScienceClass 10CBSE

How would you distinguish between baking powder and washing soda by heating?

Soln: When we heat baking powder CO2 is released which can be confirmed by passing evolved gas into lime water which will turn milky. This reaction will not happen when you heat washing soda.

ScienceClass 10CBSE

What happens when nitric acid is added to egg shell?

Nitric acid dissolved the egg shell, which is made up of Calcium carbonate. Calcium carbonate, on reacting with nitric acid, yields calcium nitrate and carbon dioxide gas.When nitric acid is added to an eggshell:The eggshell is mainly made of calcium carbonate (CaCO₃).Nitric acid reacts with calcium carbonate in a chemical reaction.What happens:The eggshell starts fizzing (bubbling).Carbon dioxide gas (CO₂) is released.The shell gradually dissolves.Chemical reaction:CaCO3+2HNO3→Ca(NO3)2+CO2+H2OFinal result:The hard shell gets eaten away.A soft membrane underneath may remain. In short: Nitric acid reacts with the eggshell, producing bubbles and dissolving the shell.

ScienceClass 10CBSE

A student prepared solutions of (i) an acid and (ii) a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless, how will she distinguish between the two?

Soln: Student can use Phenopthalein indicator to check the nature of the solution.

ScienceClass 10CBSE

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.

Soln: Ant sting release methanoic acid. Chemical formula of methanoic acid is HCOOH. If we rub baking soda on the affected area it can give relief from the discomfort caused by ant sting.

ScienceClass 10CBSE

What will be the action of the following substances on litmus paper? Dry HCl gas, Moistened NH3 gas, Lemon juice, Carbonated soft drink, Curd, Soap solution.

Soln: Dry HCl gas- No effect Moistened NH3 gas- Turns litmus paper to blue colour Lemon juice- Turns litmus paper to red colour Carbonated soft drink- Turns litmus paper to red colour Curd- Turns litmus paper to red colour Soap solution- Turns litmus paper to blue colour

ScienceClass 10CBSE

Match the important chemicals given in Column (A) with the chemical formulae given in Column (B) Column (A) Column (B) (a) Plaster of Paris (i) Ca(OH)2 (b) Gypsum (ii) CaSO4. ½ H2O (c) Bleaching Powder (iii)CaSO4.2H2O (d) Slaked Lime (iv) CaOCl2

Soln: Column (A) Column (B) (a) Plaster of Paris (ii) CaSO4. ½ H2O (b) Gypsum (iii)CaSO4.2H2O (c) Bleaching Powder (iv) CaOCl2 (d) Slaked Lime (i) Ca(OH)2

ScienceClass 10CBSE

Match the acids given in Column (A) with their correct source given in Column (B) Column (A) Column (B) (a) Lactic acid (i) Tomato (b) Acetic acid (ii) Lemon (c) Citric acid (iii) Vinegar (d) Oxalic acid (iv) Curd

Soln: Column (A) Column (B) (a) Lactic acid (iv) Curd (b) Acetic acid (iii) Vinegar (c) Citric acid (ii) Lemon (d) Oxalic acid (i) Tomato Column (A) Column (B) Lactic acid (iv) Curd Acetic acid (iii) Vinegar Citric acid (ii) Lemon Oxalic acid (i) Tomato

ScienceClass 10CBSE

Identify the correct representation of reaction occurring during chloralkali process (a) 2NaCl(l) + 2H2O(l) → 2NaOH(l) + Cl2 (g) + H2 (g) (b) 2NaCl(aq) + 2H2O(aq) → 2NaOH(aq) + Cl2 (g) + H2 (g) (c) 2NaCl(aq) + 2H2O(l) → 2NaOH(aq) + Cl2 (aq) + H2 (aq) 2NaCl (aq) + 2H2O (l) → 2NaOH (aq) + Cl2 (g) + H2 (g)

Soln: Answer is (d) 2NaCl (aq) + 2H2O (l) → 2NaOH (aq) + Cl2 (g) + H2 (g)

ScienceClass 10CBSE

Which of the following are present in a dilute aqueous solution of hydrochloric acid? (a) H3O+ + Cl– (b) H3O+ + OH– (c) Cl– + OH– unionised HCl

Soln: Answer is (a) H3O+ + Cl– Explanation: Acid produces Hydrogen which will combine with water molecule to produce Hydronium ion.

ScienceClass 10CBSE

Which of the following statements is true for acids? (a) Bitter and change red litmus to blue (b) Sour and change red litmus to blue (c) Sour and change blue litmus to red (d) Bitter and change blue litmus to red

Soln: Answer is (c) Sour and change blue litmus to red

ScienceClass 10CBSE

Which of the following is(are) true when HCl (g) is passed through water? (i) It does not ionise in the solution as it is a covalent compound. (ii) It ionises in the solution (iii) It gives both hydrogen and hydroxyl ion in the solution (iv) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule (a) (i) only (b) (iii) only (c) (ii) and (iv) (iii) and (iv)

Soln: Answer is (c) (ii) and (iv) Explanation: HCL is a strong acid which ionizes completely in water to produce Hydrogen as well as Hydrogen and chlorine. Hydrogen produces combine with water molecules to give Hydronium ions.

ScienceClass 10CBSE

Match the chemical substances given in Column (A) with their appropriate application given in Column (B) Column (A) Column (B) (A) Bleaching powder (i) Preparation of glass (B) Baking soda (ii) Production of H2 and Cl2 (C) Washing soda (iii) Decolourisation (D) Sodium chloride (iv) Antacid (a) A—(ii), B—(i), C—(iv), D—(iii) (b) A—(iii), B—(ii), C—(iv), D—(i) (c) A—(iii), B—(iv), C—(i), D—(ii) (d) A—(ii), B—(iv), C—(i), D—(iii)

Answer is (c) A—(iii), B—(iv), C—(i), D—(ii)

ScienceClass 10CBSE

Which of the following statements is not correct? (a) All metal carbonates react with acid to give a salt, water and carbon dioxide (b) All metal oxides react with water to give salt and acid (c) Some metals react with acids to give salt and hydrogen (d) Some non metal oxides react with water to form an acid

Soln: Answer is (b) All metal oxides react with water to give salt and acid Explanation: Metal oxides are basic in nature hence they give alkaline solution when dissolved in water.

ScienceClass 10CBSE

Which among the following is not a base? (a) NaOH (b) KOH (c) NH4OH (d) C2H5 OH

Soln: Answer is (d) C2H5 OH Explanation: C2H5 OH is an alcohol not a base

ScienceClass 10CBSE

Which of the following is not a mineral acid? (a) Hydrochloric acid (b) Citric acid (c) Sulphuric acid Nitric acid

Soln: Answer is (b) Citric acid Explanation: Citric acid is the organic acid hence it is the answer

ScienceClass 10CBSE

Which of the following is used for dissolution of gold? (a) Hydrochloric acid (b) Sulphuric acid (c) Nitric acid Aqua regia

Solution: Answer is (d) Aqua regia Explanation: Gold is a nobel metal which will not react even with strong acids, hence aqua regia which is a mixture of Nitric and Hydro chloric acid in the ratio 1:3 is used for dissolution of gold.

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