Modern Periodic Table and Periodic Properties — Chemistry STD 10 — Question

What is the difference between ionic compounds and polar covalent compounds.

Give reason for the following:
Extraction of aluminium was very difficult in the beginning.

Write a balanced chemical equation : when hot and concentrated sulphuric acid reacts with the following : Carbon

How are the following conversion brought about? Give equation and condition:
Oxalic acid to carbon monoxide.

Distinguish by a chemical test,
Sodium hydroxide solution and ammonium hydroxide solution.

From the following list of substances, choose one substance in each case which matches the description given below:
Ammonium nitrate, Calcium hydrogen carbonate, copper carbonate, lead nitrate, potassium nitrate, sodium carbonate, sodium hydrogen carbonate, zinc carbonate.
(a) A Substance that gives off only oxygen when heated.
(b) A Substance which on heating decomposes into dinitrogen oxide (nitrous oxide) and steam.
(c) A Substance that gives off oxygen and nitrogen dioxide when heated.
(d) A Substance which on heating leaves a yellow residue.

Why is it necessary to add acid to water before proceeding with electrolysis of water?

Explain, why during the electrolysis of copper sulphate using copper electrodes, the colour of solution does not fade?

Brown ring disappear if the test tube is disturbed.

What volume of oxygen is required to burn completely 90 dm³ of butane under similar conditions of temperature and pressure?
2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O