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प्रश्न
Fill in the blank
A new substance is formed in a _______ change.
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उत्तर
A new substance is formed in a chemical change.
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संबंधित प्रश्न
Complete and balance the following chemical equations
NaCI + `AgNO_3` `→`
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
Fill in the blank
A catalyst either ................or ............... the rate of a chemical change but itself remains ............... at the end of the reaction.
TRUE \ FALSE
Ammonia is a good oxidizing agent.
How is a strong electrolyte different from a weak electrolyte?
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)
Electron ______ is complete in each hydrogen in a hydrogen molecule.
Show with the help of diagram of electronic configuration how the following compound is formed from the constituent atoms.
Sodium chloride
Give reason for the following:
Colourless concentrated sulphuric acid in a test tube changes to blue on adding a small piece of copper to it.
State the main characteristics of chemical reactions. Give at least one example in each case.
Complete and balance the following reaction:
NaCl(aq) + AgNO3(aq) →
Give a chemical test to distinguish between the following gases.
HCl and Cl2
Give a chemical test to distinguish between the following gases.
NH3 and HCl
Give a word equation for the following reaction.
Two solids which combine on heating, to give a liquid.
Give a word equation for the following reaction.
A compound which on heating shows – colour change from brown to yellow.
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.
| Heat on ammonium dichromate | Name of neutral gas evolved |
Complete the statement by filling in the blank with the correct word:
The reddish-brown precipitate obtained during a double decomposition precipitation reaction between an iron salt and alkali is __________.
Discuss how acid rain occurs due to emission of smoke from vehicles and industries?
Rusting of iron is ______.
