Hydrogen — JEE Main PYQs

Given below are two statements:
Statement I: H₂O₂ can act as both oxidizing and reducing agent in basic medium.
Statement II: In the hydrogen economy, the energy is transmitted in the form of dihydrogen.
In the light of the above statements, choose the correct answer from the opt …

Statement I : Sodium hydride can be used as an oxidizing agent.
Statement II : The lone pair of electrons on nitrogen in pyridine makes it basic.
Choose the CORRECT answer from the options given below:

The correct statement about ${\mathrm{H}}_2{\mathrm{O}}_2$ are:
(A) Used in the treatment of effluents.
(B) Used as both oxidizing and reducing agents
(C) The two hydroxyl groups lie in the same plane.
(D) Miscible with water.

Choose the correct answer from the options given …

The functional groups that are responsible for the ion-exchange property of cation and anion exchange resins, respectively, are:

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R:
Assertion A : During the boiling of water having temporary hardness, $\mathrm{Mg}{\left({\mathrm{HCO}}_3\right)}_2$ is converted to ${\mathrm{MgCO}}_3$.
Reason R: The solubility …

In basic medium H₂O₂ exhibits which of the following reactions?
(A) Mn²⁺ → Mn⁴⁺
(B) I₂ → I⁻
(C) PbS → PbSO₄
Choose the most appropriate answer from the options given below:

In comparison to the zeolite process for the removal of permanent hardness, the synthetic resins method is

Among statements (a) - (d), the correct ones are
(a) decomposition of hydrogen peroxide gives dioxygen.
(b) like hydrogen peroxide, compounds such as ${\mathrm{KCIO}}_3,\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$ and ${\mathrm{NaNO}}_3$ when heated liberated dioxygen.
(c) …

Hydrogen has three isotopes (a), (b) and (c). If the number of neutron(s) in (a), (b) and (c) respectively, are (x), (y) and (z), the sum of (x), (y) and (z) is:

5 g of zinc is treated separately with an excess of
(a) dilute hydrochloric acid and
(b) aqueous sodium hydroxide.

The ratio of the volumes of ${\mathrm{H}}_2$ evolved in these two reactions is : -

The hardness of a water sample containing $10^{-3}\mathrm{M}{\mathrm{MgSO}}_4$ expressed as ${\mathrm{CaCO}}_3$ equivalents (in ppm) is ______.
(molar mass of ${\mathrm{MgSO}}_4$ is $120.38\mathrm{g}/\mathrm{mol}$)

Hydrogen peroxide, in the pure state, is:

The one that is NOT suitable for the removal of permanent hardness of water is:

Dihydrogen of high purity (>99.95%) is obtained through:

The equation that represents the water - gas shift reactions is:

100 mL of a water sample contains 0.81 g of calcium bicarbonate and 0.73 g of magnesium bicarbonate. The hardness of this water sample expressed in terms of equivalents of ${\mathrm{CaCO}}_3$ is:
(molar mass of calcium bicarbonate is $162{\mathrm{gmol}}^{-1}$ and magnesium bicarbo …

The total number of isotopes of hydrogen and number of radioactive isotopes among them, respectively are

The chemical nature of hydrogen peroxide is

The metal that gives hydrogen gas upon treatment with both acid as well as base is:

The correct statements among (a) to (b) are:
(a) saline hydrides produce ${\mathrm{H}}_2$ gas when reacted with ${\mathrm{H}}_2\mathrm{O}$.
(b) reaction of ${\mathrm{LiAH}}_4$ with ${\mathrm{BF}}_3$ leads to ${\mathrm{B}}_2{\mathrm{H}}_6$.
(c) ${\mathrm{PH}}_3$ and …

NaH is an example of:

The correct statements among (a) to (d) regarding ${\mathrm{H}}_2$ as a fuel are:
(a) it produces less pollutants than petrol
(b) A cylinder of compressed dihydrogen weighs $\sim 30$ times more than a petrol tank producing the same amount of energy.
(c) Dihydrogen is stored in ta …

The hardness of water sample (in terms of equivalents of $\mathrm{CaCO}{}_3$) containing $10^{-3}$ M $\mathrm{CaSO}{}_4$ is
(molar mass of CaSO${}_4$ = 136 g mol${}^{-1}$)

The temporary hardness of a water sample is due to compound X. Boiling this sample converts X to compound Y. X and Y, respectively, are :

The volume strength of $1\mathrm{M}{\mathrm{H}}_2{\mathrm{O}}_2$ is : (Molar mass of ${\mathrm{H}}_2{\mathrm{O}}_2=34\mathrm{g}{\mathrm{mol}}^{-1}$ )

The temporary hardness of water is due to

The isotopes of hydrogen are

The synonym for water gas when used in the production of methanol is

Hydrogen peroxide oxidises ${\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{4-}$ to ${\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{3-}$ in acidic medium but reduces ${\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{3-}$ to ${\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{4-}$ in alkaline medium. Th …

The most abundant elements by mass in the body of a healthy human adult are : Oxygen ( $61.4\%$ ); Carbon ( $22.9\%$ ), Hydrogen ( $10.0\%$ ); and Nitrogen ( $2.6\%$ ). The weight which a 75 kg person would gain if all ${}^1\mathrm{H}$ atoms are replaced by …

Which one of the following statements about water is FALSE?

The molecular formula of a commercial resin used for exchanging ions in water softening is ${\mathrm{C}}_8{\mathrm{H}}_7{\mathrm{SO}}_3\mathrm{Na}$ (Mol. Wt. 206). What would be the maximum uptake of ${\mathrm{Ca}}^{2+}$ ions by the resin when expressed in mole per gram resin?

From the following statements regarding ${\mathrm{H}}_2{\mathrm{O}}_2$, choose the incorrect statement:

In which of the following reactions ${\mathrm{H}}_2{\mathrm{O}}_2$ acts as a reducing agent?
(a) ${\mathrm{H}}_2{\mathrm{O}}_2+2{\mathrm{H}}^{+}+2{\mathrm{e}}^{-}⟶2{\mathrm{H}}_2\mathrm{O}$
(b) …

Very pure hydrogen ( $99.9\%$ ) can be made by which of the following processes ?

In context with the industrial preparation of hydrogen from water gas $\left(\mathrm{CO}+{\mathrm{H}}_2\right)$, which of the following is the correct statement?

Hydrogen bomb is based on the principle of