Carbon and its Compounds — Science STD 10 — Question

An element X reacts with hydrogen, when heated, to form a covalent hydride H₂X. If H₂X has a smell of rotten eggs, the element X is likely to be:

PbS reacts with ozone (O₃) and forms pbso₄. As per the balanced equation, molecules of ozone required for every one molecule of PbS is/are:

Which 3 metals are magnetic?

One of the following burns without producing a flame. This is:

compound → element + element

Fresh milk has a pH of 6. When milk changes into curd, the pH value will:

Identify the type of chemical reaction.
Mg(s) + Cl₂​(g) → MgCl₂​(s)

The elements A, B, C and D belong to groups 1, 2, 14 and 17 respectively of the periodic table. Which of the following pairs of elements would produce a covalent bond?

1. A and D.
2. C and D.
3. Aand B.
4. B and C.
5. Aand C.

In the reaction, 2FeCl₂ + Cl₂ > 2FeCl₂, chlorine may be regarded as:

The pencil leads are made of mainly:

1. Lithium.
2. Charcoal.
3. Lead.
4. Graphite.