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प्रश्न
Write true or false :
When iron and sulphur are heated together a grey mass is formed which is attracted by a magnet .
विकल्प
True
False
उत्तर
False
APPEARS IN
संबंधित प्रश्न
How do the following help in bringing about a chemical change?
heat.
Complete and balance the following chemical equations:
Fe `"SO"_4` + NaOH `→`
(aq.) (aq.)
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.
TRUE \ FALSE
Copper can displace iron from iron sulphate.
TRUE \ FALSE
Ammonia is a good oxidizing agent.
Name three reducing agents ?
Fill in the blank:
The basic conditions necessary for a chemical reaction is _______
Write true or false :
Hydrogen sulphide has rotten egg smell .
Name the type of chemical reaction shown by the following equation:
CaCO3 → CaO + CO2
Name the type of chemical reaction shown by the following equation:
Fe + CuSO4 → FeSO4 + Cu
| Reactants | Products | Type of chemical reaction |
| BaCl2(aq) + ZnSO4(aq) | H2CO3(aq) | Displacement |
| 2AgCl(s) | FeSO4(aq) + Cu(s) | Combination |
| CuSO4(aq) + Fe(s) | BaSO4↓ + ZnCl2(aq) | Decomposition |
| H2O(l) + CO2(g) | 2Ag(s) + Cl2(g) | Double displacement |
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.
What do you observe? When
Barium chloride is added to sodium sulphate solution
Give a chemical test to distinguish between the following gases.
HCl and Cl2
What do you observe when CO2 is passed through lime water first and then a little in excess.
Explain the term ‘chemical reaction’ with special reference to – ‘reactants’ and ‘products’.
Give reason for the following:
The catalytic oxidation of sulphur dioxide to sulphur trioxide is represented by a double arrow {⇌}
between the reactants and products, formed in the chemical reaction.
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.
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc carbonate to zinc oxide
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc nitrate to nitrogen dioxide
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Calcium hydroxide.
The changes in which new substance with new chemical properties are formed are ______.
______ is a natural indicator.
Classify the following as physical or chemical properties
Zinc dissolves in hydrochloric acid with the evolution of hydrogen gas.
A chemical change may involve –
When magnesium is burnt in the air, a new substance is formed which is ______.
Galvanization is a process in which ______ is coated as a layer of iron.
Write the characteristics of chemical change.
