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प्रश्न
What is observed in performing the following :
| Hydrogen | Oxygen | Carbon dioxide | Chlorine | |
| Litmus test | ||||
| Apply a burning splint to the gas | ||||
| Colour of gas | colourless | colourless | colourless | greenish-yellow |
| Odour of gas |
उत्तर
| Hydrogen | Oxygen | Carbon dioxide | Chlorine | |
| Litmus test | Neutral | Neutral | Acidic | Acidic |
| Apply a burning splint to the gas | Pale blue flame | rekindles a glowing wooden splinter. | moist blue litmus faint red | White precipitate |
| Colour of gas | colourless | colourless | colourless | greenish-yellow |
| Odour of gas | Odourless | Odourless | Odourless | Pungent, choking |
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संबंधित प्रश्न
The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change − A), then it burns (Change − B). The following statements pertain to these changes. Choose the correct one.
Fill in the blank
A new substance is always formed in a _______ change.
Balancing a chemical equation is based on
Name the type of chemical reaction shown by the following equation:
CaCO3 → CaO + CO2
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)
A colourless solution of calcium hydroxide in a test tube turns ______ on blowing in it through a blow tube for some time.
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
Complete and balance the following reaction:
Pb(NO3)2 + KI →
Give a chemical test to distinguish between the following gases.
HCl and H2S
Write your observation and a balanced equation in the case of the following substances being heated.
Zinc carbonate.
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 – Addition of dilute acid to an active metal.
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.
Complete the table given below.
| Flame test for calcium chloride | Acid used for flame test |
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Copper nitrate.
Higher order Thinking question
Peeled and unpeeled banana does not look the same. Does that mean peeling banana is a chemical change?
The changes in which new substance with new chemical properties are formed are ______.
Chemists identify gypsum as a natural indicator.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Do you think the formation of rust from iron is a chemical change?
Give an example where heat, light, and sound are produced during a chemical change.
______ is the chemical name of rust.
