A covalent bond is formed when sharing of electrons takes place between the atoms combining. The atom which attracts the shared pair of electron towards itself is more electronegative and the atom which does not attracts the shared pair of electron towards itself is less electronegative.
In HCl molecule, more electronegative atom is chlorine atom having an electronegativity of 3.16 and hydrogen has an electronegativity of 2.1
So, majority of shared electrons will be found near to the chlorine atom in hydrochloric molecule.
- Addition of Ba(OH)2: favors the formation of a precipitate.
- Undergo a chemical reaction forming soluble species.
- Addition of CuSO4 : favors the formation of a precipitate.
Explanation:
Hello,
In this case, since the dissociation reaction of barium sulfate is:
We must analyze the effect of the common ion:
- By adding barium hydroxide, more barium ions will be added to the equilibrium system so the formation of solid barium sulfate will be favored (reaction shifts leftwards towards reactants).
- By adding sodium nitrate, the following reaction will undergo:
So the precipitate will turn into other soluble species.
- By adding copper (II) sulfate, more sulfate ions will be added to the equilibrium system so the formation of solid barium sulfate will be favored (reaction shifts leftwards towards reactants).
All of this is supported by the Le Chatelier's principle.
The question is incomplete. The complete question is :
In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an explanation that tells how much NaOH needs to be added to a beaker of HCl to cause the color to change. Your explanation can be something like: The color change will occur when [some amount] of NaOH is added because the color change occurs when [some condition]. The goal for your explanation is that it describes the outcome of this example, but can also be used to predict the outcome of other examples of this phenomenon. Here's an example explanation: The color of the solution will change when 40 ml of NaOH is added to a beaker of HCl because the color always changes when 40ml of base is added. Although this explanation works for this example, it probably won't work in examples where the flask contains a different amount of HCl, such as 30ml. Try to make an explanation that accurately predicts the outcome of other versions of this phenomenon.
Solution :
Consider the equation of the reaction between NaOH and
NaOH (aq) + HCl (aq) → NaCl(aq) +
The above equation tells us that of reacts with of .
So at the equivalence point, the moles of NaOH added = moles of present.
If the volume of the taken = mL and the conc. of = mole/L
The volume of NaOH added up to the color change = mole/L
Moles of taken = moles.
The color change will occur when the moles of NaOH added is equal to the moles of taken.
Thus when
or when
or mL of NaOH added, we observe the color change.
Where are the volume and molarity of the taken.
is the molarity of NaOH added.
When both the NaOH and are of the same concentrations, i.e. if , then
Or the 40 mL of will need 40 mL of NaOH for a color change and
30 mL of would need 30 mL of NaOH for the color change (provided the concentration )