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प्रश्न
An element is soft and can be cut with a knife. If is very reactive and cannot be kept open in the air. It reacts vigorously with water. The element is most likely to be:
(a) Mg
(b) S
(c) P
(d) Na
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उत्तर
(d) Na
Na is soft and can be cut with a knife. It is very reactive and cannot be kept in open air. It reacts vigorously with water.
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संबंधित प्रश्न
_________ solution is blue in colour.
(a) CuSO4
(b) FeSO4
(c) ZnSO4
(d) Al2(SO4)3
‘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’.
You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).
A student added few pieces of aluminium metal to two test tubes A and B containing aqueous solutions of iron sulphate and copper sulphate. In the second part of her experiment, she added iron metal to another test tubes C and D containing aqueous solutions of aluminium sulphate and copper sulphate.
In which test tube or test tubes will she observe colour change? On the basis of this experiment, state which one is the most reactive metal and why.
From amongst the metals sodium, calcium aluminium, copper and magnesium, name the metal:
(i) which reacts with water only on boiling, and
(ii) another which does not react even with steam.
Which of the following elements would yield an acidic oxide.
Na, S, C, K, H
Give one example, with equation, of the displacement of hydrogen by a metal from an acid.
What is the action of water on aluminium ? Write equation of the chemical reaction involved.
What happens when a metal reacts with dilute hydrochloric acid? Explain with the help of an example.
Hydrogen is not a metal but still it has been assigned a place in the reactivity series of metals. Why?
Out of the following oxides, the amphoteric oxide is:
(a) Fe2O3
(b) Al2O3
(c) P2O5
(d) N2O
Which one of the following four metals would be displaced from the solution of its salt by the other three metals?
(a) Zn
(b) Ag
(c) Cu
(d) Mg
An element E forms an oxide E2O. An aqueous solution of E2O turns red litmus paper blue.
(a) What is the nature of the oxide E2O?
(b) State whether element E is a metal or a non-metal.
(c) Give one example of an element like E.
State and explain the reaction, if any, of the following metals with a solution of copper sulphate:
(a) Gold
(b) Copper
(c) Zinc
(d) Mercury
Which of the following reactions will not occur? Why not?
(a) MgSO4 (aq) + Cu (s) → CuSO4 (aq) + Mg (s)
(b) CuSO4 (aq) + Fe (s) → FeSO4 (aq) + Cu (s)
(c) MgSO4 (aq) + Fe (s) → FeSO4 (aq) + Mg (s)
What is the characteristic of the electronic configuration of noble gases?
Where does the metal aluminium, used in the thermit process, occurs in the reactivity series of metals?
Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?
- Good thermal conductivity
- Good electrical conductivity
- Ductility
- High melting point
Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?
