The label from a bottle of pine fresh bleach cleaner is shown - Scottish Highers Chemistry - Question 12 - 2019
Question 12
The label from a bottle of pine fresh bleach cleaner is shown.
PINE FRESH BLEACH CLEANER
WARNING! Do not use together with other products.
May release dangerous g... show full transcript
Worked Solution & Example Answer:The label from a bottle of pine fresh bleach cleaner is shown - Scottish Highers Chemistry - Question 12 - 2019
Step 1
Complete the table for compound B.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Compound B can be identified as having an ionic and positively charged head group, which means it is a cationic surfactant.
Step 2
Soaps can be made from fats and oils. Name the reaction used to make soaps from fats and oils.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The reaction used to make soaps from fats and oils is known as saponification.
Step 3
Explain fully the cleaning action of compound C.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Compound C, being a soap molecule, has a hydrophilic (water-attracting) head and a hydrophobic (water-repelling) tail. The hydrophilic head interacts with water, while the hydrophobic tail interacts with oils and grease. This dual nature allows soap to surround dirt and grease particles, forming micelles that can be easily rinsed away with water, thus facilitating the cleaning action.
Step 4
State how emulsifiers are made from edible oils.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Emulsifiers are made from edible oils through a process called esterification, where glycerol is reacted with fatty acids from the oils to produce emulsifiers such as mono- and diglycerides.
Step 5
Explain what is meant by a pure covalent bond.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A pure covalent bond occurs when two atoms share electrons equally due to the same electronegativity. In this case, there is no charge separation, and the electron density is evenly distributed between the atoms.
Step 6
Suggest why an electrophilic attack occurs.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
An electrophilic attack occurs because chlorine, being an electronegative element, creates a region of partial positive charge, making it reactive and capable of attacking electron-rich species in the sodium hydroxide solution.
Step 7
Explain clearly why mixing the bleach with an acid would shift the equilibrium to the right.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Mixing bleach with an acid introduces additional hydrogen ions (H⁺), which will react with the hypochlorite ion (OCl⁻) to form chlorine gas (Cl₂). According to Le Chatelier's principle, increasing the concentration of H⁺ will shift the equilibrium to the right, favoring the production of chlorine gas, hence increasing its release.
Step 8
Write the ion-electron equation for the reduction reaction taking place in Step 1.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The ion-electron equation for the reduction reaction is:
ightarrow ext{Cl}_2 + ext{H}_2 ext{O}$$
Step 9
Calculate the concentration, in mol/dm³, of sodium hypochlorite in the bleach.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To find the concentration of sodium hypochlorite, we can use the titration results:
[ ext{Moles of Na}_2 ext{S}_2 ext{O}_3 = ext{concentration} imes ext{volume} = 0.098 ext{ mol/dm}^3 imes 0.009 ext{ dm}^3 = 8.82 imes 10^{-4} ext{ mol}\
\text{From the reaction, } 1 ext{ mole of Na}_2 ext{S}_2 ext{O}_3 ext{ reacts with 1 mole of } OCl^-.\
\text{Thus, moles of } OCl^- = 8.82 imes 10^{-4} ext{ mol. For a 25 cm}^3 ext{ sample, concentration is:}\
C = rac{n}{V} = rac{8.82 imes 10^{-4}}{0.025} = 0.0353 ext{ mol/dm}^3.\
Join the Scottish Highers students using SimpleStudy...
