Advertisements
Advertisements
प्रश्न
Write true or false .
A black residue is formed when sugar is heated .
पर्याय
True
False
Advertisements
उत्तर
True
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.
MULTIPLE CHOICE QUESTIONS
Tick the most appropriate answer.
Reduction is a chemical reaction in which there is
- removal of hydrogen
- removal of oxygen
- addition of oxygen
- none of these
Balancing a chemical equation is based on
A solution of a substance ‘X’ is used for white washing write the reaction of the substance ‘X’ named in (a) above with water.
Give an example of a reaction where the following are involved:
Close contact
Give an example of a reaction where the following are involved:
Solution
Give reason for the following:
Silver nitrate solution is kept in coloured bottles.
Multiple choice:
Which of the following is not a characteristic of a chemical change?
State the original colour of the following substance and colour of residue obtained after heating.
Lead nitrate
Give a chemical test to distinguish between the following gases.
HCl and Cl2
Name the following:
The products obtained during ‘photosynthesis’ – which is a chemical change.
Name the following:
The type of change physical or chemical involved – ‘during respiration in human beings’.
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.
Give balanced equation for the following conversion affected by heat alone on the substance:
Zinc carbonate to zinc oxide
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Zinc carbonate.
Mention the various conditions required for a chemical reaction to occur.
What is the role of a catalyst in a chemical reaction?
A thick coating of a paste of Plaster of Paris (POP) is applied over the bandage on a fractured bone. It becomes hard on drying to keep the fractured bone immobilised. Can the change in POP be reversed?
Which of the following is a chemical change?
The simplest method of preventing rusting of iron is to coat it with oil, grease, or paint. The reason being ______.
