Advertisements
Advertisements
प्रश्न
Give a word equation for the following reaction.
A compound which on heating shows – colour change from brown to yellow.
उत्तर
Lead dioxide →Lead oxide + Oxygen
2Pb02 → 2PbO + 02 (l)
APPEARS IN
संबंधित प्रश्न
Complete and balance the following chemical equations:
Ba`"CI"_2` + `"H"_2"SO"_4` `→`
(aq.) (aq.)
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{NH3_{(g)} + HCl_{(g)} -> NH4Cl_{(s)}}\]
Give reason .
A person suffering from acidity is advised to take an antacid.
FILL IN THE BLANK
In a ............ change, new substances are formed.
TRUE \ FALSE
Weak electrolytes dissociate partially in their aqueous or fused state.
TRUE \ FALSE
Electrolytic refining is a method in which a thin coating of a metal is done over another metal.
TRUE \ FALSE
Positively charged electrode is called the anode. True or false ?
Fill in the blank
A change in which the substance can be brought back to its original state is called a _______ change.
State four conditions necessary for chemical reactions to take place.
Fill in the blank:
The substances which undergo chemical change are called _______
Balance the following equation :
Fe + H2O → Fe3O4 + H2
Name the type of chemical reaction shown by the following equation :
Fe2O3 + 2Al → Al2O3 + 2Fe
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
Explain by writing a word equation.
Hard water gets softened on mixing with a solution of washing soda.
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
The conversion of ferrous sulphate to ferric sulphate is ______ reaction.
Define Electrochemical reaction
Give an example
Name Affects the acidified K2Cr2O7 paper and also turns lime water dirty milky.
Give a chemical test to distinguish between the following gases.
H2 and O2
Give a chemical test to distinguish between the following gases.
HCl and H2S
Give a chemical test to distinguish between the following gases.
NH3 and SO2
State the following reaction represent oxidation or reduction.
\[\ce{Ag->Ag+}\]
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
What happens when cane sugar is strongly heated? Mention any two changes in it.
______ is not a chemical change.
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 |
Explain how the painting of an iron gate prevents it from rusting.
How can we prevent rusting?
Chemical changes are important in our day-to-day life. Give examples.
When milk is mixed with coffee decoction, the colour of milk and decoction changes due to ______.
Acid rain is a result of ______.
