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Principles Related to Practical Chemistry · Question 13

RE-NEET (UG) 2024MCQEasy📈 Topic in 25% papers+4−1
1

Which indicator is used in the titration of sodium hydroxide against oxalic acid and what is the colour change at the end point?

  1. Phenolphthalein, pink to yellow
  2. Alkaline KMnO4, colourless to pink
  3. Phenolphthalein, colourless to pink
  4. Methyl orange, yellow to pinkish red colour

Answer

(3) Phenolphthalein, colourless to pink

Solution

Oxalic acid is a weak acid and NaOH is a strong base; the end point lies in the basic range (pH about 8–10), so phenolphthalein is the suitable indicator.

With oxalic acid in the flask and NaOH in the burette, the solution is colourless and turns pink with the first excess drop of NaOH.

Answer: (3)

RE-NEET (UG) 2024

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2

A steam volatile organic compound which is immiscible with water has a boiling point of 250 C. During steam distillation, a mixture of this organic compound and water will boil :

  1. above 100 C but below 250 C
  2. above 250 C
  3. at 250 C
  4. close to but below 100 C
RE-NEET (UG) 2024
3

Match List-I with List-II : Choose the correct answer from the options given below :

  1. A-IV, B-II, C-III, D-I
  2. A-II, B-IV, C-III, D-I
  3. A-II, B-III, C-IV, D-I
  4. A-III, B-IV, C-II, D-I
RE-NEET (UG) 2024
4

Match List I with List II: Choose the correct answer from the options given below:

  1. A-II, B-III, C-IV, D-I
  2. A-IV, B-III, C-II, D-I
  3. A-I, B-II, C-III, D-IV
  4. A-II, B-III, C-I, D-IV
RE-NEET (UG) 2024
5

On complete combustion, 0.3 g of an organic compound gave 0.2 g of CO2 and 0.1 g of H2O. The percentage composition of carbon and hydrogen in the compound, respectively is:

  1. 4.07% and 15.02%
  2. 18.18% and 3.70%
  3. 15.02% and 4.07%
  4. 3.70% and 18.18%
RE-NEET (UG) 2024
6

In Lassaigne's extract of an organic compound, both nitrogen and sulphur are present, which gives blood red colour with Fe3+ due to the formation of-

  1. NaSCN
  2. [Fe(CN)5NOS]4-
  3. [Fe(SCN)]2+
  4. Fe4[Fe(CN)6]3 xH2O
NEET (UG) 2023
7

The Kjeldahl's method for the estimation of nitrogen can be used to estimate the amount of nitrogen in which one of the following compounds?

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
NEET (UG) 2022
8

Paper chromatography is an example of :

  1. Partition chromatography
  2. Thin layer chromatography
  3. Column chromatography
  4. Adsorption chromatography
NEET (UG) 2020
9

The most suitable method of separation of 1 : 1 mixture of ortho and para-nitrophenols is

  1. chromatography
  2. crystallisation
  3. steam distillation
  4. sublimation.
NEET 2017
10

In Dumas method for estimation of nitrogen, 0.25 g of an organic compound gave 40 mL of nitrogen collected at 300 K temperature and 725 mm pressure. If the aqueous tension at 300 K is 25 mm, the percentage of nitrogen in the compound is

  1. 16.75
  2. 15.76
  3. 17.36
  4. 18.20
AIPMT 2015 (Cancelled)
11

In the Kjeldahl's method for estimation of nitrogen present in a soil sample, ammonia evolved from 0.75 g of sample neutralized 10 mL of 1 M H2SO4. The percentage of nitrogen in the soil is

  1. 37.33
  2. 45.33
  3. 35.33
  4. 43.33
AIPMT 2014

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