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प्रश्न
State the various characteristics of chemical reactions.
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उत्तर
Following are the various characteristics of a chemical reaction:
- Evolution of gas: Zinc and dilute sulphuric acid react to form zinc sulphate with the evolution of hydrogen gas.
- Formation of precipitate: Sulphuric acid and barium chloride react to form white precipitates of barium sulphate.
- Change in colour: Purple colour of potassium permanganate solution on addition of citric acid changes to colourless solution.
- Change in temperature: Barium hydroxide and ammonium chloride react to form barium chloride, ammonia and water. This is an endothermic reaction in which heat is absorbed, causing the temperature to fall.
- Change in state: Combustion of candle wax (solid) leads to the formation of water (liquid) and carbon dioxide (gas).
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संबंधित प्रश्न
2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid.
How will you indicate Endothermic reaction in a chemical equation?
Balance the given chemical equation:
NH3 → N2 + H2
Balance the given chemical equation:
C + CO2 → CO
Write balanced chemical equation from the following information:
An aqueous calcium hydroxide solution (lime water) reacts with carbon dioxide gas to produce a solid calcium carbonate precipitate and water.
What do you understand by endothermic reactions?
You are given the solution of lead nitrate. In order to obtain a yellow precipitate you should mix with it a solution of:
(a) potassium chloride
(b) potassium nitride
(c) potassium sulphide
(d) potassium iodide
Write the balanced equation for the following chemical reaction.
\[\ce{Barium chloride + Aluminium sulphate -> Barium sulphate + Aluminium chloride}\]
Write word equation for the following skeletal equation:
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Balance the following chemical equation :
FeS + HCl → FeCl2 + H2S
Write symbolic representation for the following word equation and balance them :
Aluminium + Chlorine → Aluminium chloride.
Balance the following equation .
N2 + O2 → NO
Answer the following question.
What is observed when 2 mL of dilute hydrochloric acid is added to 1 g of sodium carbonate taken in a clean and dry test tube? Write a chemical equation for the reaction involved.
In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:
Copper [II] sulphate to sodium hydroxide.
Give word equation for the following chemical reaction and give the names of the product formed.
Zn + 2HC1→ ZnCl2 + H2
Give word equation for the following chemical reaction and give the names of the product formed.
\[\ce{CuO + H2SO4 -> CuSO4 + H2O}\]
Write word equation for the following chemical reaction given below. Also state the observation seen in the case.
\[\ce{2SO2 + O2 ⇌[V2O5][450°C] 2SO3}\]
Balance the following simple equation:
Mg + N2 → Mg3N2
Balance the following simple equation:
KBr + Cl2 → KCl + Br2
Balance the following simple equation:
NaOH + Cl2 → NaCl + NaClO + H2O
