Advertisements
Advertisements
Question
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.
Advertisements
Solution
Addition of dil. acid to an active metal: Gas is evolved, test tube or flask becomes hot (heat is produced).
APPEARS IN
RELATED QUESTIONS
Complete and balance the following chemical equations:
N2 + O2 →
Complete and balance the following chemical equations
NaCI + `AgNO_3` `→`
Complete and balance the following chemical equations:
Fe `"SO"_4` + NaOH `→`
(aq.) (aq.)
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
Fill in the blank
A new substance is always formed in a _______ change.
Fill in the blank
A new substance is formed in a _______ change.
Explain the following reaction with one suitable example of Decomposition reaction
Name: Two nitrates that do not produce nitrogen dioxide on heating.
What do you observe when H2S is passed through a lead nitrate solution.
Distinguish by heating the following in dry test tubs.
Copper Sulphate and copper carbonate
Distinguish by dilute sulphuric acid.
Sodium Sulphite and sodium carbonate?
Complete the table given below.
| Heat on sodium chloride | Colour imparted to flame during flame test |
State the following reaction represent oxidation or reduction.
\[\ce{Cu++->Cu}\]
Explain with the help of balanced equations, how precipitation reactions are used for identifying the positive radicals in three different salts, each having a different cation [positive ion].
Name the solid residual product formed reaction and state its colour during – thermal decomposition of the following substance.
Ammonium dichromate.
Discuss how acid rain occurs due to emission of smoke from vehicles and industries?
______ change results in the change of the substance.
The water we drink is a combination of hydrogen and oxygen.
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 formation of rust from iron is a chemical change?
