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प्रश्न
Give a reason.
Wasp sting is treated with vinegar.
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उत्तर
Wasp stings are alkaline and they can be neutralized by vinegar which is a weak acid.
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संबंधित प्रश्न
Give one example that illustrates the following characteristics of a chemical reaction:
Change in state
FILL IN THE BLANK
The new substances formed during a chemical reaction are called the ..................
What are the characteristics of a chemical reaction ? A chemical reaction is characterised by an irreversible change in which a new substance is formed.
A chemical equation is a statement that describes a chemical change in terms of
Complete the statement by filling the gaps using appropriate term from the terms given in the bracket.
(slow, coloured, arrow, fast, smell, milky, physical, product, chemical, reactant, covalent, ionic, octet, duplet, exchange, sharing, equality sign)
A colourless solution of calcium hydroxide in a test tube turns ______ on blowing in it through a blow tube for some time.
Explain by writing a word equation.
Respiration is a chemical change.
Choose the correct option from the bracket and explain the statement giving a reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
Addition of an aqueous solution of ZnSO4 to an aqueous solution of BaCl2 is an example of ______ reaction.
Define a photochemical reaction.
Distinguish by heating the following in dry test tubs.
Zinc carbonate, Copper carbonate and lead carbonate.
Select the correct answer for the following options:
The pale blue precipitated obtained when copper [II] sulphate reacts with sodium hydroxide.
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 dilute acid to an active metal.
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 – Thermal decomposition of mercury [II] oxide.
Complete the table given below.
| Addition of dil. H2SO4 to KHCO3 | Name of residue obtained |
Complete the table given below.
| Heat on sodium chloride | Colour imparted to flame during flame test |
Explain the term chemical reaction with special reference to reactants and products.
What is the role of a catalyst in a chemical reaction?
______ are substances that speed up the process of a chemical change and it will not undergo any change during the course of the reaction.
Which is used as a catalyst during the process of hydrogenation of oils?
How would you show that the settling of curd is a chemical change?
What is the difference between reactants and products?
