$\mathrm{NaH}$ is an example of:

Important Questions on Hydrogen

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IMPORTANT

Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 8

The correct statements among $\left(\mathrm{a}\right)$ to $\left(\mathrm{d}\right)$ regarding $H_2$ as a fuel are:

$\left(\mathrm{a}\right)$ It produces less pollutants than petrol

$\left(\mathrm{b}\right)$ A cylinder of compressed dihydrogen weighs $\sim 30$ times more than a petrol tank producing the same amount of energy

$\left(\mathrm{c}\right)$ Dihydrogen is stored in tanks of metal alloys like $NaN{i}_5$

$\left(\mathrm{d}\right)$ On combustion, values of energy released per gram of liquid dihydrogen and LPG are $50$ and $142 kJ$ , respectively
 

MEDIUM

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IMPORTANT

Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 9

The correct statements among $\left(\mathrm{a}\right)$ to $\left(\mathrm{d}\right)$ are:

$\left(\mathrm{a}\right)$ Saline hydrides produce ${\mathrm{H}}_2$ gas when reacted with ${\mathrm{H}}_2\mathrm{O}.$

$\left(\mathrm{b}\right)$ Reaction of $\mathrm{L}\mathrm{i}\mathrm{A}\mathrm{l}{\mathrm{H}}_4$ with $\mathrm{B}{\mathrm{F}}_3$ leads to ${\mathrm{B}}_2{\mathrm{H}}_6$ .

$\left(\mathrm{c}\right)$ $\mathrm{P}{\mathrm{H}}_3$ and $\mathrm{C}{\mathrm{H}}_4$ are electron - rich and electron - precise hydrides, respectively.

$\left(\mathrm{d}\right)$ $\mathrm{H}\mathrm{F}$ and $\mathrm{C}{\mathrm{H}}_4$ are called as molecular hydrides.

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Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 11

When zeolite, which is hydrated sodium aluminium silicate, is treated with hard water, the sodium ions are exchanged with

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Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 12

Polyphosphates are used as water softening agents because they 

HARD

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Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 13

A white solid is either Na₂O or Na₂O₂. A piece of red litmus paper turns white when it is dipped into a freshly made aqueous solution of the white solid.
(i) Identify the substance and explain with balanced equation.
(ii) Explain what would happen to the red litmus if the white solid were the other compound.

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Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 14

Hydorgen peroxide acts both as an oxidising and as a reducing agent depending upon the nature of the reacting species. In which of the following cases ${\mathrm{H}}_2{\mathrm{O}}_2$ acts as a reducing agent in acid medium?

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Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 15

Permanent hardness of water cannot be cured by:

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Alpha Question Bank for Engineering: Chemistry>Chapter 15 - Hydrogen>Exercise-3>Q 16

The temporary hardness of water is due to: