To solve this question we need to first look at the relationship between hydroxide and hydrogen ion concentrations:

where is concentration of hydrogen ions and is the concentration of hydroxide ions. Solve for :

We can solve for the concentration of hydrogen ions in this solution by writing the dissociation of hydrochloric acid in solution:

The question states that it is a 1M solution. Since and are in 1:1 ratio, the concentration of hydrogen ions will equal the concentration ; therefore, . Note that this won’t be the case if the acid was weak. For a weak acid, the concentration of will be less than the concentration of acid, even if it was 1:1 ratio. This occurs because a weak acid does not dissociate completely.

We can now use the to solve for .

Therefore, concentration of hydroxide ions in this solution is

To solve this question we need to first look at the relationship between hydroxide and hydrogen ion concentrations:

where is concentration of hydrogen ions and is the concentration of hydroxide ions. Solve for :

We can solve for the concentration of hydrogen ions in this solution by writing the dissociation of hydrochloric acid in solution:

The question states that it is a 1M solution. Since and are in 1:1 ratio, the concentration of hydrogen ions will equal the concentration ; therefore, . Note that this won’t be the case if the acid was weak. For a weak acid, the concentration of will be less than the concentration of acid, even if it was 1:1 ratio. This occurs because a weak acid does not dissociate completely.

We can now use the to solve for .

Therefore, concentration of hydroxide ions in this solution is

In order to determine what concentration of fluoride is needed, we can use the Henderson-Hasselbach equation:

In order to determine what concentration of fluoride is needed, we can use the Henderson-Hasselbach equation:

Oxidation is the process of losing electrons, or acquiring a more positive charge. We can determine which atom has lost electrons by comparing the oxidation number of the atom as a reactant and as a product. Aluminum is in elemental form as a reactant, so it has an oxidation number of 0. As a product, it is bonded with oxygen, giving each aluminum an oxidation number of +3. Since it has a more positive charge, the aluminum has been oxidized.

Oxidation is the process of losing electrons, or acquiring a more positive charge. We can determine which atom has lost electrons by comparing the oxidation number of the atom as a reactant and as a product. Aluminum is in elemental form as a reactant, so it has an oxidation number of 0. As a product, it is bonded with oxygen, giving each aluminum an oxidation number of +3. Since it has a more positive charge, the aluminum has been oxidized.

Recall that acids and bases can be defined in three different ways. First, the Arrhenius definition states that an acid is a substance that increases the concentration of hydrogen ions in solution whereas a base decreases hydrogen ions concentration. Second, Bronsted-Lowry definition states that an acid is any substance that donates a proton whereas a base is any substance that accepts a proton. Finally, Lewis definition states that an acid is any substance that accepts an electron pair whereas a base is a substance that donates an electron pair.

We have two substances in this question. , or borane, is considered a Lewis acid because it accepts an electron pair. Boron has four orbitals in its outermost shell. If we look at Boron in borane, we will notice that three orbitals are occupied by the electrons in the three single bonds (bound to hydrogen) whereas the last orbital is empty and is free to accept electrons. Since it accepts electrons, borane is considered a lewis acid. , or ammonia, is a lewis base. If we look at the nitrogen atom in ammonia, we will notice that all of its orbitals are occupied (three orbitals are occupied with the three bonds to hydrogen atoms and the last orbital is occupied with a lone electron pair). Since it has extra electrons in the last orbital, ammonia can donate electrons and is considered a lewis base.

Recall that acids and bases can be defined in three different ways. First, the Arrhenius definition states that an acid is a substance that increases the concentration of hydrogen ions in solution whereas a base decreases hydrogen ions concentration. Second, Bronsted-Lowry definition states that an acid is any substance that donates a proton whereas a base is any substance that accepts a proton. Finally, Lewis definition states that an acid is any substance that accepts an electron pair whereas a base is a substance that donates an electron pair.

We have two substances in this question. , or borane, is considered a Lewis acid because it accepts an electron pair. Boron has four orbitals in its outermost shell. If we look at Boron in borane, we will notice that three orbitals are occupied by the electrons in the three single bonds (bound to hydrogen) whereas the last orbital is empty and is free to accept electrons. Since it accepts electrons, borane is considered a lewis acid. , or ammonia, is a lewis base. If we look at the nitrogen atom in ammonia, we will notice that all of its orbitals are occupied (three orbitals are occupied with the three bonds to hydrogen atoms and the last orbital is occupied with a lone electron pair). Since it has extra electrons in the last orbital, ammonia can donate electrons and is considered a lewis base.

Hydrochloric acid () and sodium hydroxide () are both strong reagents. Adding equal amounts of strong acid to a strong base neutralizes the solution and gives the solution a neutral pH of 7. This means that the concentration of hydrogen ions and hydroxide ions are equal to each other. If pH was greater than 7 (basic pH), then the hydroxide ion concentration would be higher and if pH was less than 7 (acidic pH) then hydrogen ion concentration would be higher.

Hydrochloric acid () and sodium hydroxide () are both strong reagents. Adding equal amounts of strong acid to a strong base neutralizes the solution and gives the solution a neutral pH of 7. This means that the concentration of hydrogen ions and hydroxide ions are equal to each other. If pH was greater than 7 (basic pH), then the hydroxide ion concentration would be higher and if pH was less than 7 (acidic pH) then hydrogen ion concentration would be higher.