Chemistry Test ...

A solution containing \(1.8 {~g}\) of a compound (empirical formula \({CH}_{2} {O}\) ) in \(40 {~g}\) of water is observed to freeze at \(-0.465 ^{\circ} {C}\). The molecular formula of the compound is \(({K_f}\) of water \(=1.86 {~kg}\) \(\left.{kmol}^{-1}\right)\)

Determine the empirical formula of an oxide of iron which has \(69.9 \%\) iron and \(30.1 \%\) dioxygen by mass.

Hydrogen bond is strongest in:

Alkali metals give a _________________when dissolved in liquid ammonia.

The compound formed in the positive test for nitrogen with the Lassaigne solution of an organic compound is:

Which of the following is not a homologous series?

The result of the operation \(2.5 \times 1.25\) should be which of the following on the basis of significant figures?

Paramagnetism is common in:

\(1 \mathrm{~kg}\) of 0.75 molal aqueous solution of sucrose can be cooled up to \(-4^{\circ} \mathrm{C}\) before freezing. The amount of ice (in g) that will be separated out is__________(Nearest integer)

[Given, \(\mathrm{K}_{\mathrm{f}}\left(\mathrm{H}_2 \mathrm{O}\right)=1.86 \mathrm{Kkg} \mathrm{mol}^{-1}\) ]

In liquids London forces are found in: