Deck 10: Hydrogen

Question 1

Find the correct statement:

A) Tritium is an isotope of hydrogen with three nucleons.
B) Deuterium, ²H, forms weaker bonds than ¹H.
C) Ortho- and para-hydrogen are isotopes of H₂ molecule.

Answer 1

A

Question 2

Which of the following reactions can be used for small-scale (laboratory) production of H₂:
(i) Copper and concentrated HCl.
(ii) Aluminium and warm concentrated NaOH solution.
(iii) Group 17 hydride and water.

A) (i) and (iii)
B) Only (i)
C) Only (ii)

Answer 2

C

Question 3

Find the most common industrial process for the production of H₂:

A) using electrolysis of water
B) using fossil fuels and water
C) using biological methods

Answer 3

B

Question 4

Why is catalyst frequently required for the reactions involving H₂ as a reactant?

A) Hydrogen is a gas, it has low solubility. Catalyst can increase its solubility.
B) Hydrogen is a small molecule that can easily escape any reaction. Catalyst prevents this by rapidly reacting with H₂.
C) Due to the strong H-H bond, the reactions with H₂ have high activation energy. Catalyst is used to lower this activation energy.

Question 5

Under which conditions does hydrogen react via a radical mechanism?

A) in a presence of a catalyst
B) thermal or photochemical activation
C) under high-pressure conditions.

Question 6

Hydrogen forms ___________ with the majority of elements from groups 1 and 2.

A) molecular hydrides
B) metallic hydrides
C) saline hydrides

Question 7

Classify the following molecular hydrides: (i) SiH₄ (ii) PH₃ and (iii) AsH₃.

A) (i) is an electron-precise hydride, (ii) is an electron rich hydride, (iii) is an electron deficient hydride
B) All three are electron rich hydrides
C) (i) is an electron precise hydride, (ii) and (iii) are electron rich hydrides

Question 8

The metallic hydrides frequently have ____________ and ____________.

A) (constant composition) and (are hard materials)
B) (non-stoichiometry) and (metallic lustre)
C) (good solubility) and (low reactivity)

Question 9

Hydrogen bonding is important for:

A) molecular hydrides
B) metallic hydrides
C) saline hydrides

Question 10

Which of the following statements is not correct:

A) Hydride ligand can bridge two metallic centres in a polynuclear complex
B) Since hydride is considered an anionic ligand, d-block hydrides cannot behave as acids.
C) Both hydride and dihydrogen can be ligands to the same metal atom.