Neutralization and Buffers Help

Neutralization

As anyone who has ever gotten a strong acid on the skin can tell you, the reaction with skin molecules is universally a bad thing. But let’s think about it. If an accident happened and you or your lab partner were splashed with acid, would you know how to stop the reaction?

In a laboratory, get under water as quickly as possible. Whether to wash your hands, use the eye wash, or be doused in a full body shower, the action of the water dilutes the acid. This has a neutralizing effect on the reaction between the acid/base and the skin or the clothes. Another option would be to use a base to counteract the acid, but this usually takes too much time.

Canceling out of acids by bases and bases by acids is called neutralization.

Water is the best response for strong bases, too. Since they are fully ionized, they can cause the same kinds of chemical burns as acids. Sometimes students forget this and treat bases with less respect than acids. This is not a good plan. Strong acids cause the same kinds of bad burns as strong bases. Again, if in contact with a base, another option would be to counteract the base with an acid.

The key is that acids cancel out the affects of bases and bases cancel the affects of acids.

Oxidation Numbers

As we learned earlier, electrons are often shared in compounds. Sometimes they are shared fairly and sometimes one or the other of the atoms will pull electrons tighter and have more control of the electrons. Chemists keep track of this control of electrons by something called oxidation state or oxidation numbers . When atoms are surrounded only by atoms of their own kind, they share equally, but it depends on the strength of the bonding of the different atoms. In general, if control is strong and is increased in a reaction, the sign is negative. If electron control is weaker, the sign is positive.

Oxidation numbers are based on the difference between the number of electrons an atom in the element can control and the number of electrons an atom in a compound can grab and hang on to.

The table below gives tips to help you find the oxidation numbers of elements and compounds.

Table 14.4 Here are some simple ways to figure out oxidation numbers.