Write Equations for the Reactions Of Calcium and Potassium with Water - Science


 Write equations for the reactions of calcium and potassium with water



The reaction of calcium with water is exothermic but the heat evolved is not sufficient for the hydrogen to catch fire. 

Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g) + Heat

Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal.
Potassium react violently with cold water and its reaction is so violent and exothermic that the evolved hydrogen immediately catches fire.

2K (s) + 2H2O (l) → 2KOH (aq) + H2 (g) + Heat

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Chapter 3: Metals and Non-metals - Intext Questions [Page 45]


NCERT Science Class 10
Chapter 3 Metals and Non-metals
Intext Questions | Q 2.2 | Page 45


Metal A has electronic configuration (2, 8, 1) and metal B has (2, 8, 8, 2). Which is more reactive? Why? Identify these metals.

_________ solution is blue in colour.
(a) CuSO4
(b) FeSO4
(c) ZnSO4
(d) Al2(SO4)3

Iron is
(a) More reactive than zinc
(b) More reactive than aluminium
(c) Less reactive than copper
(d) Less reactive than aluminium

Name the following:
Metals which forms an amphoteric oxide.

‘E’ is an element which reacts with oxygen to form an oxide E2O. An aqueous solution of E2O turns red litmus blue, so:
i. What is the nature of oxide E2O ?
ii. Write the name of element ‘E’.

Write equations for the reactions of iron with steam 

The solution of Aluminium sulphate in water is .....................

(a) Green

(b) Colourless

(c) Pink

(d) Blue

The reaction of an iron nail with copper sulphate solution is ........... reaction.

(a) Combination

(b) Displacement

(c) Double displacement

(d) Decomposition

Explain the following reaction with the help of a balanced chemical equation:
Magnesium reacts with hot water.

State whether the following statement is true or false:
Non-metals react with dilute acids to produce a gas which burns with a 'pop' sound.

Write equation for the reaction of sodium with oxygen.

What special name is given to substances like aluminium oxide.

Name one metal more reactive and another less reactive than hydrogen.

What are noble gases

What is the characteristic of the electronic configuration of noble gases?

Choose the correct alternative and rewrite the following:

Reaction of iron nails whith copper sulphate solution is an example of _____________________

Choose the correct alternative and rewrite the following:

Which of the following is lue in colour?

Calcium floats over water during the reaction with water. Give reason.  

Write the chemical equation of the above process.

Rewrite the following statement by selecting the correct option.
A solution of Al2(SO4)3 in water is _____________.

Generally, metals are solid in nature. Which one of the following metals is found in liquid state at room temperature?

An alkali metal A gives a compound B (molecular mass = 40) on reacting with water. The compound B gives a soluble compound C on treatment with aluminium oxide. Identify A, B and C and give the reaction involved.

Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?

Which of the following property is not responsible for copper to be used as electrical conduction wires?

Find the odd one out:

Tungsten wire is used in electric bulbs.

Why is acidified water considered to be a good conductor of electricity?


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