1

### JEE Main 2018 (Online) 16th April Morning Slot

For standardizing NaOH solution, which of the following is used as a primary standard ?
A
Ferrous Ammonium Sulfate
B
dil. HCl
C
Oxalic acid
D
Sodium tetraborate
2

### JEE Main 2018 (Online) 16th April Morning Slot

In a complexometric titration of metal ion with ligand
M(Metal ion) + L(Ligand) $\to$ C(Complex) end point is estimated spectrophoto - metrically (through light absorption). If 'M' and 'C' do not absorb light and only 'L' absorbs, then the titration plot between absorbed light (A) versus volume of ligand 'L' (V) would look like :
A
B
C
D
3

### JEE Main 2019 (Online) 9th January Morning Slot

The correct match between Item-I and Item-II is :

Item-I (drug) Item-II (test)
A Chloroxylenol P Carbylamine test
B Norethindrone Q Sodium hydrogen carbonet test
C Sulphapyridine R Ferric chloride test
D Penicillin S Bayer's test
A
A $\to$ R;  B $\to$ P;  C $\to$ S;  D $\to$ Q
B
A $\to$ Q;  B $\to$ S;  C $\to$ P;  D $\to$ R
C
A $\to$ R;  B $\to$ S;  C $\to$ P;  D $\to$ Q
D
A $\to$ Q;  B $\to$ P;  C $\to$ S;  D $\to$ R

## Explanation

(1)  To react with FeCl3, with benzene ring there should be a $-$OH group attached.

(2)  For carbylamine test there should be $-$NH2 group in a compound.

(3)  NaHCO3 reacts when there is $-$COOH group in a compound.

(4)  For Bayer's test there should be double bond or tripple bond between two carbon.

4

### JEE Main 2019 (Online) 10th January Morning Slot

If dichloromethane (DCM) and water (H2O) are used for differential extraction, which one of the following statements is correct ?
A
DCM and H2O would stay as upper and lower layer respectively in the separating funnel (S.F.)
B
DCM and H2O will make turbid/colloidal mixture
C
DCM and H2O would stay as lower and upper layer respectively in the separating funnel(S.F).
D
DCM and H2O will be miscible clearly

## Explanation

Density of DCM = 1.39 and density of H2O = 1.0.

As density of DCM is higher than H2O so DCM will stay lower in separating funnel.