Advertisements
Advertisements
प्रश्न
Fill in the blank:
In some chemical reactions an insoluble ________ is formed when two solutions are mixed.
उत्तर
In some chemical reactions an insoluble precipitate is formed when two solutions are mixed.
APPEARS IN
संबंधित प्रश्न
When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.
Complete and balance the following chemical equations:
Zn + `"H"_2"SO"_4` `→`
(dil)
Give reason.
Acidic soil is treated with quick lime.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer
Which of the following is a reducing agent?
- oxygen
- chlorine
- hydrogen
- none of these
FILL IN THE BLANK
Distillation is a method of obtaining pure ............. from a solution.
How is a strong electrolyte different from a weak electrolyte?
Fill in the blank:
The substances which undergo chemical change are called _______
Write true or false.
A chemical equation gives only qualitative information of a chemical reaction.
Name the type of chemical reaction shown by the following equation:
Fe + CuSO4 → FeSO4 + Cu
State the conditions necessary for a chemical change or reaction.
Give an example of the following chemical change.
Two gases combine to form white solid
Give reason for the following:
Blue solution of copper sulphate changes to green when a piece of iron is added to this solution.
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 an example of the following chemical changes.
A reaction involving
(i) Change of state
(ii) formation of precipitate
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
Distinguish by heating the following in dry test tubs.
Zinc carbonate, Copper carbonate and lead carbonate.
Give examples of exothermic reactions i.e. heat evolved in each of the following:
(a) reaction between a solid and a liquid
(b) reaction between two gases
Give two examples of exothermic reactions seen in everyday life.
Name the following:
The products obtained during ‘photosynthesis’ – which is a chemical change.
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.
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
State the following reaction represent oxidation or reduction.
\[\ce{Al->Al+++}\]
Select the correct answer from the options given below:
State the gaseous product formed, when
An ammonium salt reacts with an alkali.
______ gas causes tears in our eyes while cutting onions.
Can a nickel spatula be used to stir copper sulphate solution? Justify your answer.
Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.
Chemists identify gypsum as a natural indicator.
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 |
When carbon dioxide is passed through lime water ______.
What are the chemical reactions that occur in everyday life?