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प्रश्न
Read the text below and answer the questions that follow:
A small amount of hydrochloric acid was taken in a test tube. The test tube was heated. A glass rod was dipped in the ammonia solution and held on the top of the test tube. A white smoke was seen emanating from the tip of the glass rod.
- What must have happened?
- Which colour of gas is formed?
- Write the chemical equation for the reaction.
उत्तर
- Due to heating, HCl vapours started coming out from the test tube, and NH3 gas came out from the solution on the glass rod. The ammonia gas and hydrogen chloride gas reacted to form the salt ammonium chloride in the gaseous state first, but immediately due to the condensation process at room temperature, it got transformed into the solid state.
- As a result white smoke was formed.
- The chemical equation for this is as follows:
\[\ce{\underset{Ammonia}{NH3(g)} + \underset{Hydrogen chloride}{HCl(g)} -> \underset{Ammonium chloride}{NH4Cl(s)}}\]
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संबंधित प्रश्न
A solution of a substance ‘X’ is used for white washing.
- Name the substance ‘X’ and write its formula.
- Write the reaction of the substance ‘X’ named in (i) above with water.
Write the balanced chemical equation for the following and identify the type of reaction.
\[\ce{Hydrogen(g) + Chlorine(g) -> Hydrogen chloride (g)}\]
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?
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.
What type of chemical reaction take place when a magnesium wire is burnt in air?
What type of chemical reaction take place when ammonia and hydrogen chloride are mixed?
What type of chemical reaction is represented by the following equation?
A + B → C
what tpye of reaction is the following:
2K + Cl → 2KCl
What type of reaction is represented by the following equation?
CaO + CO2 → CaCO3
Give one example of a combination reaction which is also endothermic.
Define a chemical reaction.
Give one example each of which illustrates the following characteristics of a chemical reaction:
change of colour
Fill in the blank
A reaction in which two or more substances combine to form a single substance is called a ............ reaction.
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{CaCO3_{(s)} ->[heat]CaO_{(s)} + CO2_{(g)}}\]
Explain the terms with examples.
Combination reaction
Define: Chemical combination reaction
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
Classify the following reaction into –
- Direct combination
- Decomposition
- Displacement
- Double decomposition
The reaction is – Molten zinc at high temperatures, burns in air to give zinc oxide.
Give a balanced equation for –
A direct combination reaction involving two elements, one of which is a non-metal
Give a balanced equation for the following type of reaction:
A reaction of direct combination i.e. synthesis in which twp gases combine to give another gas – which turns lime water milky.
The number of products formed in a synthesis reaction is ______
Define a combination reaction. Give one example of an exothermic combination reaction.
Which of the following is not a physical change?
Combustion reactions are always ____________.
The respiration process during which glucose undergoes slow combustion by combining with oxygen in the cells of our body to produce energy is a kind of:
The chemical reaction between copper and oxygen can be categorized as ______.
The Salt Story
From: The New Indian Express 9 March 2021
The salt pans in Marakkanam, a port town about 120 km from Chennai are the third largest producer of salt in Tamil Nadu. Separation of salt from water is a laborious process and the salt obtained is used as raw materials for manufacture of various sodium compounds.
One such compound is Sodium hydrogen carbonate, used in baking, as an antacid and in soda acid fire extinguishers.
The table shows the mass of various compounds obtained when 1litre of sea water is evaporated.
| COMPOUND | FORMULA | MASS OF SOLID PRESENT /g |
| Sodium Chloride | NaCl | 28.0 |
| Magnesium Chloride | MgCl2 | 8.0 |
| Magnesium Sulphate | MgSO4 | 6.0 |
| Calcium Sulphate | CaSO4 | 2.0 |
| Calcium Carbonate | CaCO3 | 1.0 |
| TOTAL AMOUNT OF SALT OBTAINED | 45.0 | |
Which compound in the table reacts with acids to release carbon dioxide?
Identify the correct option from the given table which represents the type of reactions occurring in step 1 and step 2.
Identify the types of chemical reactions occurring during the combustion of fuel:
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.
