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Stainless steel is a very useful material for our life. In stainless steel, iron is mixed with (a) Ni and Cr (b) Cu and Cr (c) Ni and Cu (d) Cu and Au

Answer: (a) Ni and Cr Stainless steel is an alloy of Iron, Nicker and chromium. This alloy makes the metal strong,... View Article

Galvanisation is a method of protecting iron from rusting by coating with a thin layer of (a) Gallium (b) Aluminium (c) Zinc (d) Silver

Answer: (c) Zinc Galvanizing is a process in which iron or steel is coated with a thin layer of zinc to protect them... View Article

Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining? (i) Au (ii) Cu (iii) Na (iv) K (a) (i) and (ii) (b) (i) and (iii) (c) (ii) and (iii) (d) (iii) and (iv)

Answer: (a) (i) and (ii) The metals obtained by various reduction processes are not very pure. They contain impurities that must... View Article

Which of the following metals exist in their native state in nature? 1) Cu 2) Au 3) Zn 4) Ag (a) (i) and (ii) (b) (ii) and (iii) (c) (ii) and (iv) (d) (iii) and (iv)

Answer: (c) (ii) and (iv) Gold and silver are non-reactive metals and they exist in the native state of nature. Metals at... View Article

Which one of the following properties is not generally exhibited by ionic compounds? (a) Solubility in water (b) Electrical conductivity in solid-state (c) High melting and boiling points (d) Electrical conductivity in a molten state

Answer: (b) Electrical conductivity in solid-state NaCl and other ionic compounds have a high melting and boiling point. They are more... View Article

Which of the following are not ionic compounds? (i) KCl (ii) HCl (iii) CCl4 (iv) NaCl (a) (i) and (ii) (b) (ii) and (iii) (c) (iii) and (iv) (d) (i) and (iii)

Answer: (b) (ii) and (iii) HCl and CCl4 are covalent compounds; hence they cannot be ionic. Covalent bonding are found in... View Article

The composition of aqua-regia is (a) Dil.HCl: Conc. HNO3 3: 1 (b) Conc.HCl: Dil. HNO3 3 : 1 (c) Conc.HCl: Conc.HNO3 3 : 1 (d) Dil.HCl: Dil.HNO3 3: 1

Answer: (c) Conc.HCl : Conc.HNO3 3 : 1 Aqua regia is a yellow-orange or sometimes red colour fuming liquid. Aqua... View Article

Generally, metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)? (a) H2 SO4 (b) HCl (c) HNO3 (d) All of these

Answer: (c) HNO3 Hydrogen gas is not evolved when a metal reacts with nitric acid because nitric acid is a... View Article

What happens when calcium is treated with water? (i) It does not react with water (ii) It reacts violently with water (iii) It reacts less violently with water (iv) Bubbles of hydrogen gas formed stick to the surface of calcium (a) (i) and (iv) (b) (ii) and (iii) (c) (i) and (ii) (d) (iii) and (iv)

(d) (iii) and (iv) In the case of calcium, the interaction with water is less violent, and hydrogen begins to... View Article

Which of the following oxide(s) of iron would be obtained on the prolonged reaction of iron with steam? (a) FeO (b) Fe2O3 (c) Fe3O4 (d) Fe2O3 and Fe3O4

Answer: (c) Fe3O4 The chemical equation for the reaction of iron with steam can be written as 3Fe(s) + 4H2O... View Article

Which one of the following metals does not react with cold as well as hot water? (a) Na (b) Ca (c) Mg (d) Fe

Answer: (d) Fe Sodium, calcium, and magnesium are metals that are strongly reactive to water and form hydroxides. Iron is... View Article

Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same? (i) Good thermal conductivity (ii) Good electrical conductivity (iii) Ductility (iv) High melting point (a) (i) and (ii) (b) (i) and (iii) (c) (ii) and (iii) (d) (i) and (iv)

Answer: (d) (i) and (iv) Aluminium is ductile and has a high electrical conductivity, which makes it unsuitable for utensil... View Article

The ability of metals to be drawn into thin wires is known as (a) ductility (b) malleability (c) sonorousity (d) conductivity

Answer: (a) ductility Metals are minerals or substances that form naturally below the surface of the Earth. Most metals are... View Article

Which of the following property is generally not shown by metals? (a) Electrical conduction (b) Sonorous in nature (c) Dullness (d) Ductility

Answer: (c) Dullness Metals are minerals or substances that form naturally below the surface of the Earth. Most metals are... View Article

Identify the compound X on the basis of the reactions given below. Also, write the name and chemical formulae of A, B and C.

Answer: (1) 2NaOH + Zn → Na2ZnO2 + H2(g) (2) NaOH + HCl → NaCl + H2O (3) NaOH +... View Article

A sulphate salt of Group 2 element of the Periodic Table is a white, soft substance, which can be moulded into different shapes by making its dough. When this compound is left in the open for some time, it becomes a solid mass and cannot be used for moulding purposes. Identify the sulphate salt, and why does it show such behaviour? Give the reaction involved.

Answer: The sulphate salt should be calcium sulphate which is white and soft substance. Calcium sulphate is popularly known as... View Article

A dry pellet of a common base B, when kept in the open absorbs moisture and turns sticky. The compound is also a by-product of the chloralkali process. Identify B. What type of reaction occurs when B is treated with an acidic oxide? Write a balanced chemical equation for one such solution.

Answer: A compound which is a byproduct of the chloralkali process is NaOH. Hence compound B is NaOH. When NaOH... View Article

A metal carbonate X on reacting with acid gives a gas which when passed through a solution Y gives the carbonate back. On the other hand, a gas G that is obtained at the anode during electrolysis of brine is passed on dry Y, and it gives a compound Z, used for disinfecting drinking water. Identity X, Y, G and Z.

Answer: Here, X is calcium carbonate (CaCO3) Y is slaked lime Z is bleaching powder (CaOCl2) G is chlorine gas X is Calcium. When calcium carbonate... View Article

For making a cake, baking powder is taken. If at home, your mother uses baking soda instead of baking powder in cake, (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?

Answer: (a) If we use baking soda instead of baking powder taste of the cake will be bitter. Upon heating... View Article

In the following schematic diagram for the preparation of hydrogen gas, as shown in Figure, what would happen if the following changes are made? (a) In place of zinc granules, the same amount of zinc dust is taken in the test tube (b) Instead of dilute sulphuric acid, dilute hydrochloric acid is taken (c) In place of zinc, copper turnings are taken (d) Sodium hydroxide is taken in place of dilute sulphuric acid, and the tube is heated.

Answer: (a) In place of zinc granules, the same amount of zinc dust is taken in the test tube If... View Article

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