Combination Reactions Video Lecture | Chemistry Class 11 - NEET

welcome to electron line and now we're
going to take a look at the first of the
five types of redox reactions called the
combination reaction and as the name
would indicate combination reactions
where you're combining two elements so
in this case I have some examples we
have sulfur and oxygen notice that
sulfur in a solid state and oxygen in
the gas state they both have the
oxidation number of zero because then
they're in their natural common state
when they combine sulfur goes to an
oxidation state of plus four and oxygen
two - - so that means sulfur is being
oxidized and oxygen is being reduced
notice that since there's two oxygens
two times minus 2 is minus 4 so now that
adds up to zero so the oxidation number
on both sides of the equation so to
speak are our balanced the next one we
have barium in a solid state and
fluorine gas we combine those notice
that barium goes to an oxidation state
of plus two and fluorine goes to minus
one of course there's two of them to
balance out the equation and so we end
up with barium fluoride the third
equation is when we have carbon combined
with oxygen gas again they're in the
natural States oxidation number zero it
becomes carbon dioxide carbon gets
oxidized to +4 and oxygen minus 2 being
reduced to minus two there's two of them
so two times minus 2 is minus 4 and
again it's balanced on both sides of the
equation the next one we have chlorine
gas and it's being combined with you
know what we're gonna need to here
chlorine gas is a diatomic molecule now
we got it correct all right so we have
chlorine gas and we have phosphorus
trichloride come together this is a
liquid there's a gas that combined forms
a solid phosphorus pentachloride notice
that the oxidation state from Foster's
friend went from plus 3 to plus 5 and it
therefore had an ability to get two more
chlorines in its molecule and finally we
have nitrogen gas and hydrogen gas when
they combine it forms ammonia gas notice
the oxidation number for both gases is
zero in the natural state they come
together
nitrogen is not being reduced to minus
three hydrogen is oxidized to plus one
you have to have three of them to
balance out the equation again the
equation is balanced the via the oxy
Dasia numbers so there's some nice
example some simple examples of what we
mean with combination reactions there
are definitely oxidation reduction
reactions