Tag: materials we use

Quizzes (1) Questions (39)

Questions Related to materials we use

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

When $NaOH$ is used in making of soap, it is called as:

  1. alkali soap

  2. soft soap

  3. hard soap

  4. none of above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Soaps are sodium or potassium salts of long chain fatty acids. When triglycerides in fat/oil react with aqueous $NaOH$ or $KOH$, they are converted into soap and glycerol.  The sodium salt of long chain fatty acid is known as hard soap. It is difficult to dissolve in water. It is used as laundry soap.

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

Assertion: Hard water consumes more soap.
Reason: The ion responsible for cleansing action is precipitated out by $Ca^{2+}$ or $Mg^{2+}$ ion.

  1. Assertion is correct but Reason is wrong.

  2. Assertion is correct but Reason is right.

  3. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.

  4. Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Hard water consumes more soap because hard water contains dissolved salts of calcium, magnesium and other heavy metals and it does not form lather with soap readily, due to the reaction shown below.

$2RCOONa + Ca^{2+}  \rightarrow (RCOO) _2 Ca + 2 Na^+$

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

Soaps are formed by saponification of?

  1. alcohols

  2. glycosides

  3. simple esters

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

Saponification is formation of soaps from triglycerides (esters) when reacted with sodium hydroxide to give sodium salts of fatty acids.

$\underbrace {C _2H _5COOCH _3} _{Esters}+NaOH\longrightarrow C _2H _5CO\overset {\circleddash}{O}Na+C _2H _3OH$

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

Which of the following pairs of ions makes the water hard?

  1. $Na^+$
  2. $Cs^+$
  3. $Rb^+$
  4. $Ba^{+2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ion-exchange resin can soften both temporary and permanent hard water. The ion-exchange resin starts with sodium ions struck to it. As the bond water passes through the column, sodium ions come off the resin and go into the water.

Thus, ${ Na }^{ + }$ ions makes the water hard.

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

Soaps cannot be used in hard water because they:

  1. contain sodium

  2. form precipitates

  3. create environmental problems

  4. create ozone depletion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Soaps cannot be used in hard water because they forms precipitates. When soaps are used in hard water that contains a lot of calcium and magnesium ions they cause the soap to precipitate and it is unable to form lather. This can be minimized by the addition of chemicals like sodium trimetaphosphate, borax, sodium silicate etc. These prevent the calcium and magnesium ions from reacting with the soap and allow it to form lather, thus forming precipitates.

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

Which of the following statement is not correct ? 

  1. KCI is a substitute for NaCI for patients of high blood pressure.

  2. KOH is a stronger alkali than NaOH

  3. KOH is used in the manufacture of soft soap.

  4. NaOH is a non-deliquescent white crystalline solid.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Sodium hydroxide (NaOH) is a deliquescent white crystalline solid that absorbs moisture from the atmosphere and dissolves in it, making the statement that it is non-deliquescent incorrect. The other statements regarding KCl as a salt substitute, KOH being a strong alkali used in soft soaps, are chemically accurate.

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

Assertion : In O/W emulsion, soap is mixed
Reason : Soap reduces surface tension

  1. If both assertion and reason are true and reason is the correct explanation of assertion.

  2. If both assertion and reason are true but reason is not the correct explanation of assertion.

  3. If assertion is true but reason is false.

  4. If both assertion and reason are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For emulsification soap is added in O/W emulsion as it reduces surface tension and form better colloid.

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

Fertilisers are used to provide three elements needed to increase the yield of crops.
Which two compounds would provide all three of these elements?

  1. ammonium nitrate and calcium phosphate

  2. ammonium nitrate and potassium sulfate

  3. potassium nitrate and calcium phosphate

  4. potassium nitrate and potassium sulfate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\text{All fertilizer labels have three bold numbers. The first number is the }$$\text{the second number is the amount of phosphate and the third number is the amount of potas. }$$\text{These three numbers represent the primary nurtients (nitrogen(N)-phosphorus(P)-potassium(K)).}$