Tag: soap and detergents

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Questions Related to soap and detergents

Multiple choice chemistry materials we use soap and detergents soap soap and detergent

Sodium hydroxide is found in:

  1. lime water

  2. milk of magnesia

  3. window cleaner

  4. soap
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\bullet$ Lime water has $Ca(OH) _2$

$\bullet$ Milk of magnesia has $Mg(OH) _2$
$\bullet$ Window cleaner has $NH _4OH$
$\bullet$ Soap consists of sodium stearate and $NaOH$.

Multiple choice chemistry materials we use soap and detergents soap soap and detergent

A product obtained by mixing caustic soda with vegetable oils is:

  1. acid

  2. base

  3. soap

  4. vinegar
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When vegetable oils reacted with caustic soda they produce potassium salt of Carboxylate. (Soap)

$\implies Vegetable\ oil+KOH\longrightarrow \underbrace {R-CO\overset {\circleddash}{O}K} _{soap}$

Multiple choice chemistry materials we use soap and detergents soap soap and detergent

Which type of chemical substances is disparlure?

  1. Detergent

  2. Antioxidant

  3. Pheromones

  4. Preservative
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Disparlure is a pheromones that attracts insects. Pheromones are an additional form of chemical communication that occurs between rather than within individuals.

Multiple choice chemistry materials we use soap and detergents soap soap and detergent

The soap molecule has a :

  1. hydrophilic head and a hydrophobic tail

  2. hydrophobic head and a hydrophilic tail

  3. hydrophobic head and a hydrophobic tail

  4. hydrophilic head and a hydrophilic tail
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The basic structure of all soaps is essentially the same, consisting of a long hydrophobic (water-fearing) hydrocarbon chain tail and a hydrophilic (water-loving) anionic head.

Hence the correct option is A.
Multiple choice chemistry materials we use soap and detergents soap soap and detergent

Washing soaps produce scum with hard water and not much foam because hard water contains:

  1. chalk and sulphur

  2. many dissolved inorganic salts

  3. many suspended particles

  4. organic matter
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hard water contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Ferrous ion may also be present; oxidized to the ferric form. It appears as a reddish brown stain on washed fabrics and enameled surfaces. Water hardness that is caused by calcium bicarbonates is known as temporary, because boiling converts the bicarbonates to the insoluble carbonates; hardness from other salts is called permanent. Calcium and magnesium ions in hard water react with the higher fatty acids off soap to form an insoluble gelatinous curd, thereby causing a waste of the soap.

Multiple choice chemistry materials we use soap and detergents soap soap and detergent

Face powders are used for a smooth appearance of the skin by covering any unwanted secretions of oil. Which is the main ingredient of face powder?

  1. Precipitates

  2. Talc

  3. Zinc oxide

  4. Zinc stearate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Talc is often considered to be the main ingredient of face powder. Talc also known as French chalk, is a naturally occurring minerals that absorbs moisture and oil. It leaves the skin feeling soft and fresh and can help to control shine.

Multiple choice chemistry materials we use soap and detergents soap soap and detergent

Ordinary gasoline (petrol) that is used as fuel cars, scooters and automobiles contain many different chemicals that are added in small quantities, each performing an important role. Some of these are mentioned here. Which of the option is false?

  1. Soaps used for removing particles of grease from petrol tanks ensure a free flow of petrol

  2. Anti-icing agents are used for depressing the freezing point of particles of ice

  3. Anti-rust agents are used for protecting against corrosion by water

  4. Detergents are used for preventing gums from sticking on the walls of the carbureter
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\bullet$ Anti- rust agents are used for protecting iron materials against corrosion by water. Example- Redoxide.

$\bullet$ Anti-icing agents are used for depressing the freezing point of particles of ice.
$\bullet$ Soaps only grease particles from clothes, but it can't remove grease from petrol.

Multiple choice chemistry materials we use soap and detergents soap soap and detergent

Soaps are sodium salts of fatty acids, RCOONa; e.g. $C _{17}H _{35}COO^-Na^+$. It gives an insoluble precipitate / layer with 

  1. $Ca^{2+}$ (aq)
  2. $Mg^{2+}$ (aq)

  3. HCl (aq)

  4. All of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Soaps are sodium salts of fatty acids. It gives an insoluble precipitate/layer with Calcium, Magnesium ions. It also gives an insoluble layer with HCl acid.

As a cleaning agent, soap suffers from two main drawbacks:

  • It does not function well in acidic solutions because of the formation of insoluble fatty acid 
eg, $CH _3(CH _2) _{16}COO^-Na^+(aq) + HCl(aq) \rightarrow CH _3(CH _2) _{16}COOH(s) + Na^+(aq) + Cl^-(aq)$
  • It forms insoluble precipitates with $Ca^{2+}$ and$ Mg^{2+}$ ions present in hard water, forming a scum 
eg, $2CH _3(CH _2) _{16}COO^-Na^+(aq) + Ca^{2+}(aq) \rightarrow [CH _3(CH _2) _{16}COO^-] _2Ca^{2+}(s) + 2Na^+(aq)$