Answer : The coefficient of hydrogen gas in the balanced equation is, 4
Explanation :
Balanced chemical reaction : It is defined as the reaction in which the number of atoms of individual elements present on reactant side must be equal to the product side.
Single replacement reaction : It is defined as a reaction in which the the more reactive element replace the less reactive element.
The balanced chemical reaction will be:

In this reaction, lead is more reactive element than hydrogen so it can displace hydrogen element form its compound and form lead(IV) nitrate.
Thus, the coefficient of hydrogen gas in the balanced equation is, 4
Gravity is a force that always attracts or pulls objects toward each other without direct contact or impact. Gravitational attraction depends on the mass of the two objects and the distance they are apart. Objects on Earth are pulled toward the center of Earth.
The sun also heats up the air in the atmosphere at the equator. This air will move towards the poles & cool over time. In the process, wind that occurs due to air currents will introduce currents at the surface of the ocean. Wind & Air
Answer:
14 is this value for a molecule of
.
Explanation:
Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.
In the Lewis-dot structure the valance electrons are shown by 'dot'.
Number of total outer valence electrons is carbon = 4
Number of total outer valence electrons is hydrogen = 1
Number of total outer valence electrons is chlorine = 7
For total number of outer electrons is 

14 is this value for a molecule of
.