Carbon and its Compounds — Science STD 10 — Question

Which of the following is not an endothermic reaction?

Out of aluminium, copper, calcium and tin, the most reactive metal is:

1. Aluminium.
2. Copper.
3. Tin.
4. Calcium.

Which of the following statement is correct in regard to the classification of elements?

1. Elements in modern periodic table are arranged on the basis of increasing atomic masses.
2. Elements in Mendeleev's periodic table are arranged on the basis of increasing atomic numbers.
3. In modern periodic table, the element nickel of lower atomic mass is kept before the element cobalt of higher atomic mass.
4. In modern periodic table, the isotopes of chlorine having different atomic masses are kept in the same group.

10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount of HCl solution (the same solution as before) required to neutralise it will be

Which of the following is a decomposition reaction?

A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue?

The aqueous solutions of copper sulphate and zinc sulphate appear:

A salt whose aqueous solution will have a pH of more than 7 will be:

1. K₂CO₃
2. K₂SO₄
3. NaCl
4. NH₄Cl

One of the following organic compounds cannot decolourise the red-brown colour bromine water. This compound is:

The atomic number of an element Y is 17. The number of electrons in its ion Y⁻ will be: