Which of the following statements with regard to heating of lead nitrate powder over a flame are correct?

$1.$ Brown fumes of $\mathrm{NO}$ are released.

$2.$ Colourless ${\mathrm{O}}_2$ gas is released.

$3.$ It is an example of oxidation reaction.

$4.$ It is an example of thermal decomposition used for the production of ${\mathrm{NO}}_2$ gas.

Select the correct answer using the code given below.

Identify the incorrect statement for the reaction $2{\mathrm{H}}_2\mathrm{S}+{\mathrm{SO}}_{2 }\to 3\mathrm{S}+2{\mathrm{H}}_2\mathrm{O}$ is:

(Atomic mass of $\mathrm{S}=32$)

The visible universe is estimated to contain ${10}^{22}$ stars. How many moles of stars are present in the visible universe.

What is the maximum number of states of matter?

The reaction of the burning of carbon in oxygen is represented by equation

$\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right) \stackrel{}{\to } {\mathrm{CO}}_2\left(\mathrm{g}\right)+\mathrm{Heat}+\mathrm{Light}$

When 9.0 g of solid carbon is burnt in 16.0 g of oxygen gas the mass of carbon dioxide gas formed would be:

(Note: Atomic mass of C-12,o u, O=16.0 u)

The molecular mass of sulphuric acid is $98$. If $49$ g of the acid is dissolved in water to make one litre of solution, what will be the strength of the acid?

How many hydrogen atoms are contained in $1.50$g of glucose (C₆H₁₂O₆)?

The phenomenon of scattering of light by colloidal particles is called ______.