Metals and Non-Metals — Science STD 10 — Question

Explain the following in terms of gain or loss of oxygen with one example:

1. Oxidation.
2. Reduction.

Blue litmus solution is added to two test tubes A and B containing dilute HCl and NaOH solution respectively. In which test tube a colour change will be observed? State the colour change and give its reason.

How are waste products excreted in Amoeba?

Translate the following statements into chemical equations and then balance them.

1. Hydrogen gas combines with nitrogen to form ammonia.
2. Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
3. Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
4. Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

What is the nature of the oxide SO? What happens when it is dissolved in water ? Write the chemical equation of the reaction involved.

Gregor Mendel’s first law of genetics states “Of a pair of contrasted characters", only one can be represented in a gamete by its internal ‘factor’.

"Burning of fossil fuels results in global warning''. Give reasons to justify this statement.

How were the positions of isotopes of an element decided in the modern periodic table?