1. What is the molecular formula of hydrogen gas?
A.
H
B.
H2
C.
H3
D.
H2O
Correct Answer:
H2
Explanation:
Hydrogen gas exists as diatomic molecules, with two hydrogen atoms joined together, so its molecular formula is H2.
2. How many hydrogen atoms are present in one molecule of molecular hydrogen?
A.
One
B.
Two
C.
Three
D.
Four
Correct Answer:
Two
Explanation:
A molecule of hydrogen is H2, meaning it contains two hydrogen atoms.
3. What type of bond joins the two hydrogen atoms in an H2 molecule?
A.
Ionic bond
B.
Metallic bond
C.
Single covalent bond
D.
Coordinate bond
Correct Answer:
Single covalent bond
Explanation:
The two hydrogen atoms in H2 share one pair of electrons, forming a single covalent bond.
4. What is the shape of a molecular hydrogen molecule, H2?
A.
Linear
B.
Bent
C.
Trigonal planar
D.
Tetrahedral
Correct Answer:
Linear
Explanation:
An H2 molecule contains only two atoms, so the atoms lie along a straight line and the molecule is linear.
5. What is the nature of the H–H bond in molecular hydrogen?
A.
A weak ionic attraction
B.
A strong covalent bond
C.
A hydrogen bond
D.
A metallic bond
Correct Answer:
A strong covalent bond
Explanation:
The hydrogen atoms share electrons strongly in H2, forming a strong H–H covalent bond.
6. What is the relative molecular mass of H2? (H = 1)
A.
1
B.
2
C.
3
D.
4
Correct Answer:
2
Explanation:
An H2 molecule contains two hydrogen atoms, so its relative molecular mass is 1 + 1 = 2.
7. Which statement correctly describes the H2 molecule?
A.
It contains two hydrogen ions
B.
It contains two hydrogen atoms sharing electrons
C.
It contains one hydrogen atom and one oxygen atom
D.
It contains two hydrogen atoms joined by an ionic bond
Correct Answer:
It contains two hydrogen atoms sharing electrons
Explanation:
Molecular hydrogen consists of two neutral hydrogen atoms that share a pair of electrons through a covalent bond.
8. What is the polarity of the H2 molecule?
A.
Strongly polar
B.
Weakly polar
C.
Nonpolar
D.
Ionic
Correct Answer:
Nonpolar
Explanation:
The two atoms in H2 are identical and attract the shared electrons equally, making the molecule nonpolar.
9. Which type of molecular hydrogen has the nuclear spins of its two hydrogen nuclei parallel?
A.
Para-hydrogen
B.
Ortho-hydrogen
C.
Atomic hydrogen
D.
Ionized hydrogen
Correct Answer:
Ortho-hydrogen
Explanation:
In ortho-hydrogen, the nuclear spins of the two hydrogen nuclei are parallel.
10. Which type of molecular hydrogen has the nuclear spins of its two hydrogen nuclei opposite?
A.
Ortho-hydrogen
B.
Para-hydrogen
C.
Atomic hydrogen
D.
Hydrogen ion
Correct Answer:
Para-hydrogen
Explanation:
In para-hydrogen, the nuclear spins of the two hydrogen nuclei are opposite or antiparallel.
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