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प्रश्न
Give reason .
A person suffering from acidity is advised to take an antacid.
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उत्तर
An antacid neutralizes stomach acidity.
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संबंधित प्रश्न
How do the following help in bringing about a chemical change?
light.
How do the following help in bringing about a chemical change?
catalyst .
Fill in the blanK
A .............is a substance which changes the rate of a chemical reaction without undergoing a chemical change.
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
Distillation is a method of obtaining pure ............. from a solution.
What are the characteristics of a chemical reaction ? A chemical reaction is characterised by an irreversible change in which a new substance is formed.
Give an example of the following chemical change.
A reaction where colour change is noticed
Give reason for the following:
Silver nitrate solution is kept in coloured bottles.
What do you understand by precipitation reaction? Explain with examples.
Give an example of the following chemical changes.
A reaction involving
(i) Change of state
(ii) formation of precipitate
Give a chemical test to distinguish between the following gases.
CO2 and SO2
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.
Give balanced equation for the following conversion affected by heat alone on the substance:
Copper nitrate to nitrogen dioxide
State the following reaction represent oxidation or reduction.
\[\ce{Ag->Ag+}\]
What happens when cane sugar is strongly heated? Mention any two changes in it.
Silver metal can displace hydrogen gas from nitric acid.
Write word equations for two chemical reactions with the help of materials given in the box.
| Air, copper sulphate, iron, vinegar, iron oxide, carbon dioxide, iron sulphate, copper, lime water, water |
When magnesium is burnt in the air, a new substance is formed which is ______.
Write a note on the following:
Curdling of milk
Assertion (A): Cutting paper into very small pieces is an irreversible change.
Reason (R): Physical changes are always reversible.
