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Oil and Fat containing food items are flushed with Nitrogen. Why?

Answer: The main objective of flushing Nitrogen into food packets containing oil and fat products is to avoid rancidity, which results when the... View Article

A shiny brown coloured element ‘X’ on heating in the air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.

Answer: copper The shiny brown coloured element is Copper metal. As copper is heated in the air, it reacts with oxygen in the air to form black... View Article

Explain the following in terms of gain of oxygen with two examples each. (a) Oxidation (b) Reduction

Answer: Oxidation and reduction reactions are two chemical reactions that often occur together. There is an electron exchange in this reaction.... View Article

In the refining of Silver, the recovery of silver from Silver nitrate solution involves displacement reaction by Copper metal. Write down the reaction involved.

Answer: Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag(s) The type of reaction is a displacement reaction. A displacement reaction is one wherein... View Article

What is meant by exothermic and endothermic reactions? Give examples.

Answer: In a chemical reaction, energy is used for breaking the bonds of the reactants also energy is used in formation of new bonds. So, there... View Article

Write a balanced chemical equation for the following and identify the type of reaction of each case KBr + BaI² → KI + BaBr² ZnCO³ → ZnO + CO² H²+ Cl → HCl Mg + HCl → MgCl² + H²

Answer: The representation of a chemical reaction in the form of substances is known as a chemical equation. The equation in which the number of... View Article

Translate the following statements into chemical equations and balance them. (a) Hydrogen gas combines with nitrogen to form ammonia. (b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (c) Barium chloride reacts with aluminium sulphate to give Aluminium chloride and a precipitate of barium sulphate. (d) Potassium metal reacts with water to give potassium hydroxide and Hydrogen gas.

Answer: The representation of a chemical reaction in the form of substances is known as a chemical equation. The equation in which the number of... View Article

What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer. (1) Hydrogen gas and Iron chloride are produced. (2) Chlorine gas and Iron hydroxide are produced. (3) No reaction takes place. (4) Iron salt and water are produced.

Answer: (1) Hydrogen gas and iron chloride are produced. Let us consider the reaction between acid and metal Acid + Metal → Salt + Hydrogen... View Article

Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) → 2Pb(s) + CO2(g) (a) Lead is getting reduced (b) Carbon Dioxide is getting oxidised (c) Carbon is getting oxidised (d) Lead oxide is getting reduced (i) (a) and (b) (ii) (a) and (c) (iii) (a), (b) and (c) (iv) all

Answer: (i) (a) and (b) 2PbO(s) + C(s) → 2Pb(s) + CO2(g) Reduced substance - Pb Pb2+ + 2e- → Pb Pb gains electrons or its oxidation number... View Article

Identify the substances that are oxidized and that are reduced in the following equation. (i) 4Na(s) + O₂(g) → 2Na₂O(s) (ii) CuO(s) + H₂(g) → Cu(s) + H₂O(l)

Answer: The oxidized substance is called a reduction agent. The reduced substance is called an oxidizing agent. (i) 4Na(s) + O2(g) →... View Article

Write a balanced chemical equation with state symbols for the following reactions (i) Solutions of Barium chloride and Sodium sulphate in water react to give insoluble Barium sulphate and solution of Sodium chloride. (ii) Sodium hydroxide solution in water reacts with hydrochloric acid solution to produce Sodium chloride solution and water.

Answer: The representation of a chemical reaction in the form of substances is known as a chemical equation. The equation in which the number of... View Article

M	T	W	T	F	S	S
					1	2
3	4	5	6	7	8	9
10	11	12	13	14	15	16
17	18	19	20	21	22	23
24	25	26	27	28	29	30
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Archives

Oil and Fat containing food items are flushed with Nitrogen. Why?

A shiny brown coloured element ‘X’ on heating in the air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.

Explain the following in terms of gain of oxygen with two examples each. (a) Oxidation (b) Reduction

In the refining of Silver, the recovery of silver from Silver nitrate solution involves displacement reaction by Copper metal. Write down the reaction involved.

What is meant by exothermic and endothermic reactions? Give examples.

Write a balanced chemical equation for the following and identify the type of reaction of each case KBr + BaI² → KI + BaBr² ZnCO³ → ZnO + CO² H²+ Cl → HCl Mg + HCl → MgCl² + H²

What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer. (1) Hydrogen gas and Iron chloride are produced. (2) Chlorine gas and Iron hydroxide are produced. (3) No reaction takes place. (4) Iron salt and water are produced.

Which of the statements about the reaction below are incorrect? 2PbO(s) + C(s) → 2Pb(s) + CO2(g) (a) Lead is getting reduced (b) Carbon Dioxide is getting oxidised (c) Carbon is getting oxidised (d) Lead oxide is getting reduced (i) (a) and (b) (ii) (a) and (c) (iii) (a), (b) and (c) (iv) all

Identify the substances that are oxidized and that are reduced in the following equation. (i) 4Na(s) + O₂(g) → 2Na₂O(s) (ii) CuO(s) + H₂(g) → Cu(s) + H₂O(l)

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