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2020 WAEC Chemistry Practical C is an organic compound. Carry out the following exercises on C. Record your observations and...

Chemistry
WAEC 2020

C is an organic compound. Carry out the following exercises on C. Record your observations and identity any gas(es) evolved. State the conclusions you draw from the results of each test.

(a) Put about 10 drops of C on a watch glass and ignite it using a burning splint.

(b)(i) Put about 1 cm\(^3\) of C in a test tube and add about 1 cm\(^3\) of distilled water. Shake the test tube.

(ii) Put about 1 cm\(^3\) of C in a test tube and add about 2 cm\(^3\) of acidified K\(_2\)Cr\(_2\)O\(_7\) solution. Warm the mixture gently and leave to stand for 5 minutes.

(c) Put few crystals of specimen D in a test tube and add about 2cm\(^3\) of C followed by about 2 cm\(^3\) of 10 % NaOH\(_{(aq)}\) Shake the test tube vigorously.

(d) State the class of compounds to which C belongs.
 

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Explanation
  Test Observation

inference

(a)  C on a water glass + burning splint Burns with a non-Soothy/blue flame

Saturated organic compound may be present

(b)(i) C + distilled water + shaking One layer formed/miscible/viscous mixture/ C dissolved

C is soluble

(ii) C + acidified K\(_2\)Cr,\(_2\)O\(_{7(aq)}\)  warm and leave to stand for 5 minutes Orange solution turns green

C is oxidized/reducing agent K\(_2\)Cr,\(_2\)O\(_{7(aq)}\) is reduced/Oxidizing agent or Primary or secondary alkanol present 

(c) D\(_{(s)}\) + C + NaOH\(_{(aq)}\) shaking vigorously Yellow Yellow precipitate forms with antiseptic smell lod foam produced

 

(d) Alkanols


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WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
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WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709
WAEC May/June 2024 - Practice for Objective & Theory - From 1988 till date, download app now - 99995
WAEC offline past questions - with all answers and explanations in one app - Download for free
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC Past Questions, Objective & Theory, Study 100% offline, Download app now - 24709