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प्रश्न
What is a chemical reaction?
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उत्तर
“Chemical reaction is a chemical change in which matter changes into a new substance or substances.”
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संबंधित प्रश्न
Give a reason.
Wasp sting is treated with vinegar.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer
Which of the following is a reducing agent?
- oxygen
- chlorine
- hydrogen
- none of these
TRUE \ FALSE
A precipitation reaction takes place only in a solution.
Explain the type of reactions on the basis of the direction of reaction.
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
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)
Rusting of iron is a ______ chemical change.
Complete and balance the following reaction:
\[\ce{NH3 + O2 ->[\Delta]}\]
What do you observe when dilute sulphuric acid is added to the following:
Sodium Sulphide
Name the following:
The products obtained during ‘photosynthesis’ – which is a chemical change.
On heating which of the following substances i.e. copper carbonate, zinc carbonate, washing soda, copper sulphate, zinc nitrate, copper nitrate, lead nitrate, ammonium chloride and ammonium dichromate – relate to the reaction given below.
A coloured substance which leaves on strong heating a black residue and evolves two colourless gases one of which is acidic and the other neutral.
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Zinc carbonate.
When lithium metal is placed in hydrochloric acid, _______ gas is evolved.
The changes in which new substance with new chemical properties are formed are ______.
Two chemical species X and Y combine together to form a product P which contains both X and Y
\[\ce{X + Y -> P}\]
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following concerning the species X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition
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.
Which of the following is a chemical change?
How can we prevent rusting?
Write a note on the catalyst.
Chemical changes are important in our day-to-day life. Give examples.
What is the difference between reactants and products?
