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प्रश्न
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
उत्तर
The basic conditions necessary for a chemical reaction is close contact .
APPEARS IN
संबंधित प्रश्न
What are oxides ?
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
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction reaction is the exact opposite of
- displacement reaction
- decomposition reaction
- oxidation reaction
- none of these
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Compounds, which in their molten state allow an electric current to pass through them are called
- electrolytes
- non-electrolytes
- non-conductors
- none of these
FILL IN THE BLANK
On reaction with sulphuric acid solution, barium chloride forms a white precipitate of ........ sulphate.
MATCH THE COLUMNS
| 1 . `H_2` + `CI_2` `→` 2HCI | a. displacement reaction |
| 2. `2FeCI_3`+ `H_2` `→` `2FeCI_2` +2HCI` | b. addition of an electronegative redical |
| 3. Fe + `CuSO_4` `→``FeSO_4` +Cu` | c. removal of an electronegative redical |
| 4. `2H_2O` +`4NO_2`+`O_2` `→` `4HNO_3` | d.reduction by adding hydrogen |
| 5. 3Fe +`3CI_2` `→` `2FeCI_3` | e.electrolysis of water |
| 6. `FeCI_3`+ 3NaOH `→``Fe(OH)_3``↓`+NaCI | F.double decomposition,precipitation reaction |
| 7.`2H_2O` `→` `2H_2``↑`+`O_2` | e. combination or synthesis reaction |
Explain the type of reactions on the basis of the direction of reaction.
Write a short note on the information derived from a balanced chemical equation.
Fill in the blank.
Melting of ice is a _______ change.
Write true or false :
Hydrogen sulphide has rotten egg smell .
State what you would observe when the following substance is heated in a glass test tube Copper (II) carbonate Red lead .
A solution of a substance ‘X’ is used for white washing Name the substance ‘X’ and write its formula.
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.
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)
Chlorine (Cl2) molecule is formed by ______ of electrons between two chlorine atoms.
What is a chemical reaction?
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.
What do you observe? When
Sodium chloride solution is added to silver nitrate solution.
Complete and balance the following reaction:
NaCl(aq) + AgNO3(aq) →
What do you observe when Cl2 is passed through potassium iodide (KI) solution.
Give a chemical test to distinguish between the following gases.
HCl and Cl2
Distinguish by heating the following in dry test tubs.
Zinc nitrate and copper nitrate.
Select the correct answer for the following options:
The black residue obtained on heating copper carbonate.
Give a word equation for the following reaction.
Two solids which combine on heating, to give a liquid.
Give balanced equation for the following conversion affected by heat alone on the substance:
Hydrated copper sulphate to sulphur dioxide
Complete the table given below.
| Heat on sodium chloride | Colour imparted to flame during flame test |
Explain the Silver nitrate solution is kept in coloured reagent bottles in the laboratory.
Give two examples where a chemical reaction is accompanied by a change in colour of the reactants and products on completion of the reaction.
_____ is the basic material to manufacture urea.
Explain how the painting of an iron gate prevents it from rusting.
______ is the chemical name of slaked lime.
