Advertisements
Advertisements
प्रश्न
A silvery-white metal X taken in the form of ribbon, when ignited, burns in air with a dazzling white flame to form a white powder Y. When water is added to powder Y, it dissolves partially to form another substance Z.
(a) What could metal X be?
(b) What is powder Y?
(c) With which substance metal X combines to form powder Y?
(d) What is substance Z? Name one domestic use of substance Z.
(e) Write a balanced chemical equation of the reaction which takes place when metal X burns in air to form powder Y.
उत्तर
(a) Metal X could be magnesium metal.
(b) Powder Y is magnesium oxide (MgO).
(c) Magnesium metal (X) combines with oxygen gas to form powdery magnesium oxide (Y).
(d) Substance Z is magnesium hydroxide [Mg(OH)2]. Suspension of magnesium hydroxide (Z) is used as an antacid.
(e) 2Mg (s) + O2 (g) → 2MgO (s)
APPEARS IN
संबंधित प्रश्न
When crystals of copper sulphate are strongly heated, the residue obtained is ___________.
(A) red in colour
(B) blue in colour
(C) green in colour
(D) colourless
What happens chemically when quicklime is added to water filled in a bucket?
Gas A, which is the major cause of global warming, combines with hydrogen oxide B in nature in the presence of an environmental factor C and a green material D to form a six carbon organic compounds E and a gas F. The gas F is necessary for breathing.
(a) What is gas A?
(b) What is the common name of B?
(c) What do you think could be C?
(d) What is material D? Where is it found?
(e) Name the organic compound E.
(f) What is gas F? Name the natural process during which it is released.
Give one example of a combination reaction which is also endothermic.
What happens during a chemical reaction ?
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{CaCO3_{(s)} ->[heat]CaO_{(s)} + CO2_{(g)}}\]
Calcium oxide reacts vigorously with water to produce slaked lime.
\[\ce{CaO{(s)} + H2O(l) -> Ca(OH)2(aq)}\]
This reaction can be classified as:
(A) Combination reaction
(B) Exothermic reaction
(C) Endothermic reaction
(D) Oxidation reaction
Give a balanced equation for –
A direct combination reaction involving two elements, one of which is a non-metal
Balance the following chemical equation and identify the type of chemical reaction.
`"CaO"("s") + "SiO"_2("s") -> "CaSio"_3("s")`
A clear solution of slaked lime is made by dissolving Ca(OH)2 in an excess of water. This solution is left exposed to air. The solution slowly goes milky as a faint white precipitate forms. Explain why a faint white precipitate forms, support your response with the help of a chemical equation.