Carbon and its Compounds — Science STD 10 — Question

The aqueous solution of one of the following salts will turn phenolphthalein indicator pink. This salt is:

1. KCl
2. K₂SO₄
3. K₂CO₃
4. KNO₃

Dry raisins were soaked in water for 2 hours, to determine the percentage of water absorbed by raisins.Before final weighing of swollen raisins, the extra water left on the surface of soaked raisins was removed by:

Generally, non-metals are not conductors of electricity. Which of the following is a good conductor of electricity?

Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of
the following correctly represents the type of the reaction involved?
i. Displacement reaction
ii. Precipitation reaction
iii. Combination reaction
iv. Double displacement reaction

Wasp sting contains:

1. A sugar solution.
2. An acidic liquid.
3. A salt solution.
4. An alkaline liquid.

What is formed when zinc reacts with sodium hydroxide?

You have four test tubes, A, B, C and D containing sodium carbonate, sodium chloride, lime water and blue litmus solutions respectively. Out of these the material of which test tube/test tubes would be suitable for the correct test of acetic/ethanoic acid?

While studying saponification reaction for the preparation of soap, the teacher suggested to a student to add a small quantity of common salt to the reaction mixture. The function of common salt in this reaction is to:

According to Mendeleev's periodic law, the elements were arranged in the periodic table in the order of:

1. Decreasing atomic numbers.
2. Increasing atomic numbers.
3. Decreasing atomic masses.
4. Increasing atomic masses.

Which of the following is not an example of decomposition reaction?