Advertisements
Advertisements
प्रश्न
Write true or false :
Hydrogen sulphide has rotten egg smell .
विकल्प
True
False
Advertisements
उत्तर
True
APPEARS IN
संबंधित प्रश्न
Changes in which new substances are formed are called ______ changes.
Write the missing reactants and products and balance the equations.
\[\ce{KClO3 ->[heat]}\] ___________+ ____________
Write the missing reactants and products and balance the equations.
................+ HCI `→` NaCI + `"H"_2"O"` + .........................
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Which one of the following alters the rate of the chemical reaction without itself undergoing any change?
- temperature and Pressure
- concentration of reactants
- presence of catalyst
- none of these
Write balanced chemical equations for the reactions represented by word equations in the conditions for chemical reaction.
Explain the following reaction with one suitable example of Displacement reaction.
Define a photochemical reaction.
Complete and balance the following reaction:
Pb(NO3)2 + KI →
State the original colour of the following substance and colour of residue obtained after heating.
Ammonium dichromate
State the original colour of the following substance and colour of residue obtained after heating.
Zinc carbonate
Distinguish by heating the following in dry test tubs.
Ammonium Chloride and iodine.
Select the correct answer for the following options:
The basic gas obtained when two gases react in presence of a catalyst and the reaction is exothermic.
What is a chemical reaction?
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 hydrochloric acid to silver nitrate.
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 a black residue and evolves two gases one of which is acidic and coloured and the other neutral and colourless.
Assertion: The formation of iron oxide from iron is a chemical change.
Reason: For the rust to form from iron, it must be exposed to air and water.
Photosynthesis is a chemical reaction that takes place in the presence of ______.
Match the following:
| 1. | Sodium Chloride | a. | CaSO41/2H2O |
| 2. | Calcium sulphate dihydrate | b. | C2H5Oh |
| 3. | Magnesium sulphate hydrate | c. | CaSO4.2H2O |
| 4. | Calcium sulphate hemihydrate | d. | NaCl |
| 5. | Phenol | e. | MgSO4.H2O |
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
What changes do you expect?
Photosynthesis is a chemical charge. Justify your answer.
