Advertisements
Advertisements
प्रश्न
What do you observe when a piece of sodium is dropped into cold water?
Advertisements
उत्तर
When a piece of sodium metal dropped in cold water we observe: Sodium floats on water surface melts forming a silvery globule which darts about the surface of water catches fire and burns with golden yellow flame.
Bubbles of hydrogen evolve and solution is soapy, slightly warm (alkaline) hence turns red litmus blue.
APPEARS IN
संबंधित प्रश्न
Indicate which of the following statement is true and which is false:
Hydrogen gas is easily liquefiable.
Complete and balance the following equation:
H2+____________→ 2HCI
Multiple Choice Question
Equal volumes of hydrogen and chlorine are exposed to diffused sunlight to prepare
MULTIPLE CHOICE QUESTIONS
The name hydrogen was given by
- Cavendish
- Lavoisier
- Haber
- none of these
Write the balanced equation and give your observation when the following metal reacts:
Calcium with cold water
Write the balanced equation and give your observation when the following metal reacts:
Magnesium with boiling water
Choose terms from the options given in brackets to complete this sentence.
A metal …………….. hydrogen in the activity series gives hydrogen with …………… acid or …………… acid.
(above, below, dilute hydrochloric, concentrated hydrochloric, dilute sulphuric).
How is hydrogen separated from carbon dioxide and carbon monoxide?
Using a burning candle and a jar of hydrogen – how would you prove experimentally that Hydrogen does not support combustion.
With reference to the equation : Cl2 + H2S → 2HCl + S pertaining to a redox reaction – select the correct answer.
Chlorine acts as an ______ agent.
Match the statements in List I with the appropriate answer in List II.
| List I | List II |
| 1. An atom of hydrogen | A: Chromic oxide |
| 2. A strong oxidising agent | B: Ammonia |
| 3. A promoter used in Bosch process | C: Iron |
| 4. A chemical used in the manufavture of fertilizers | D: One electron |
| 5. The catalyst used in production of a basic gas from nitrogen. | E: Dilute nitric acid |
Give a chemical test to distinguish between the following gases:
Hydrogen and oxygen
What do the following symbols [or formula] denote : 2H ; H2 ; H+. [two atoms, molecule, ion]
When steam is passed over red-hot iron, magnetic oxide of iron and hydrogen are obtained. “The reaction between steam and red-hot iron is a Reversible Reaction.” What is meant by this statement.
Write balanced equation for the following reaction:
magnesium + dil. hydrochloric acid → ___
Describe one chemical test applied to the following gases, which would enable you to distinguish between them :‘carbon monoxide and hydrogen’.
What do the following symbols represent : 2H and H2.
Give balanced equation for obtaining hydrogen from cold water using a monovalent active metal.
Select the correct answer from the symbol in the bracket.
The element, which like hydrogen has one valence electron.
