Advertisements
Advertisements
प्रश्न
Give reason.
Wasp sting is treated with vinegar.
उत्तर
Wasp stings are alkaline and they can be neutralized by vinegar which is a weak acid.
APPEARS IN
संबंधित प्रश्न
State whether the following statement is true or false. In case a statement is false, write the corrected statement.
Formation of manure from leaves is a physical change.
Complete and balance the following chemical equations:
N2 + O2 →
FILL IN THE BLANK
Negatively charged ions are called ..........
FILL IN THE BLANK
In a ............ change, new substances are formed.
Fill in the blank:
The substances formed as a result of a chemical reaction are called _______
Fill in the blank:
In some chemical reactions an insoluble ________ is formed when two solutions are mixed.
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
A chemical equation is a statement that describes a chemical change in terms of
Explain the following reaction with one suitable example of Double decomposition reaction.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Hydrogen chloride
Give an example of the following chemical change.
Two gases combine to form white solid
Multiple choice:
Which of the following is not a characteristic of a chemical change?
Multiple choice:
A reaction of a type: AB + CD → AD + CD, involves
Give reason for the following:
Electrolytic decomposition of water is a reaction involving change of state.
A chemical reaction is often accompanied by external indications or characteristics which include –
- Colour change
- Effervescence or gas evolved
- Evolution or absorption of heat
- Formation of a precipitate.
With reference to each of the above indications, state the external indication seen during – Addition of water to quicklime.
Complete the table given below.
| Heat on copper carbonate | Test for gas evolved |
Explain the term chemical reaction with special reference to reactants and products.
Give two examples where a chemical reaction is accompanied by a change in colour of the reactants and products on completion of the reaction.
Give a balanced equation for a reaction involving the evolution of gas on the addition of dilute acid to sodium sulphite.
Give a balanced equation for the conversion of an ammonium salt to a basic gas.
Explain with the help of balanced equations, how precipitation reactions are used for identifying the positive radicals in three different salts, each having a different cation [positive ion].
The chemical change is ______.
Analogy:
H2O: Water:: NaCl: ______.
Classify the following as physical or chemical properties
Most metal oxides form alkalis on interacting with water.
On heating calcium carbonate gets converted into calcium oxide and carbon dioxide.
(a) Is this a physical or a chemical change?
(b) Can you prepare one acidic and one basic solution by using the products formed in the above process? If so, write the chemical equation involved.
The simplest method of preventing rusting of iron is to coat it with oil, grease, or paint. The reason being ______.
Write a note on the catalyst.
Chemical changes are important in our day-to-day life. Give examples.
