Hydrogen Test - 12

(i) Oxygen (or air) and an ignition source are required for combustion to occur.

(ii) Hydrogen burns with a pale blue flame that is nearly invisible in daylight.

(iii) The flame may appear yellow if there are impurities in the air like dust or sodium.

(iv) A pure hydrogen flame will not produce smoke.

\(2K \overset{+7}{Mn}O_4 + 3H_2SO_4 + 5H_2O_2\) → \(K_2SO_4 + 2\overset{+2}{Mn}SO_4 + 8H_2O + 5O_2\)

\(H_2O_2\) is acting as a reducing agent. It reduces \(KMnO_4\) to \(Mn^{2+}\) ion

(i) EDTA can form four or six coordination bonds with a metal ion.

(ii) Total hardness is due to the presence of bicarbonates, chlorides, and sulphates of calcium and magnesium ions.

(iii) The total hardness of water is estimated by titrating the water sample against EDTA using  Ferrochrome Black-T (EBT) indicator.

(i) The nucleus of a tritium atom consists of a proton and two neutrons.

(ii) This contrasts with the nucleus of an ordinary hydrogen atom (which consists solely of a proton) and a deuterium atom (which consists of one proton and one neutron).

(i) Tritium, the radioactive isotope of hydrogen, has one proton and two neutrons.

(ii) Uranium-235 and Uranium-238, two isotopes of the element.

(iii) Uranium, both have 92 protons, but they have 143 and 146 neutrons, respectively.

Hydrogen cannot be prepared by the action of dil. \(H_2SO_4\) on copper or mercury as these two metals cannot displace hydrogen from acids.

Action of dil. \(H_2SO_4\) on Pb stops after some time due to the formation of insoluble \(PbSO_4\). Only, iron reacts rapidly with dil. \(H_2SO_4\) to give \(H_2\).

\(H_2O\) is oxidizing agent that's reason it is not a reducing agent.

Ortho and para-hydrogen are similar in chemical properties but differ in some of the physical properties.

(i) Melting point of para-hydrogen is 13.83K while that of ordinary hydrogen is 13.95 K.

(ii) Boiling point of para hydrogen 20.26K while that of ordinary hydrogen is 20.39K.

(i) The ortho and para hydrogen differ in the nature of the spin of protons.

(ii) In ortho hydrogen, the spin of the proton is in the same direction, while in para-hydrogen the spin of the proton is in opposite direction in hydrogen molecules.

\(Mg + 2HNO_3 \rightarrow Mg (NO_3)_2 + H_2 \uparrow\)

Alkali metals are good reducing agents because of low ionization energy and hydrogen also shows same character.

\(K_2SO_4.Al_2 (SO_4)_3 .24H_2O\) Potash alum is generally used for purifying water.

We know that \( 2H_2O_2 \rightarrow 2H_2O + O_2\)

2 x 34g in 22400ml

\(\because\) 2 x 34gm = 68gm of \(H_2O_2\) liberates 22400 ml \(O_2\) at STP

\(\therefore\) 68gm of \(H_2O_2\) liberates

= \(68 \times \frac{2240}{068}\)

 = 224ml

Due to plumbosolvancy, lead dissolves in water to a small extent to form soluble hydroxide which is poisonous so lead pipe is not used for carrying drinking water.

Temporary hardness of water is due to the presence of bicarbonates of calcium and magnesium while permanent hardness is due to the presence of soluble chlorides and sulphates of calcium and magnesium.

Semi-water gas is a mixture of water gas and producer gas made by passing a mixture of air and steam through heated coke.

Hoope's process Purification of Al.

Le-Blanc process → Manufacture of \(Na_2CO_3\)

Lane's proces → Manufacture of \(H_2\) (by passing steam over spongy iron at 773-1050K) \(3Fe + 4H_2O \rightarrow Fe_3O_4 + 4H_2\)

Carter's process → manufacture of basic lead carbonate.

Ice floats on water because it is less dense than water. When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions.

The first chemical element is Hydrogen and the last is Ununoctium.

\(M^+ H^- \rightarrow M^+ + H^-  \) \( H^- \rightarrow \frac{1}{2} H_2 + e^-\) (at anode).