1
JEE Main 2023 (Online) 24th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

$$\mathrm{K_2Cr_2O_7}$$ paper acidified with dilute $$\mathrm{H_2SO_4}$$ turns green when exposed to

A
Sulphur dioxide
B
Sulphur trioxide
C
Hydrogen sulphide
D
Carbon dioxide
2
JEE Main 2023 (Online) 24th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Which of the following is true about freons?

A
These are radicals of chlorine and chlorine monoxide
B
These are chemicals causing skin cancer
C
All radicals are called freons
D
These are chlorofluorocarbon compounds
3
JEE Main 2023 (Online) 24th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Which of the Phosphorus oxoacid can create silver mirror from $$\mathrm{AgNO_3}$$ solution?

A
$$\mathrm{H_4P_2O_5}$$
B
$$\mathrm{H_4P_2O_7}$$
C
$$\mathrm{(HPO_3)_n}$$
D
$$\mathrm{H_4P_2O_6}$$
4
JEE Main 2022 (Online) 29th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

When borax is heated with $$\mathrm{CoO}$$ on a platinum loop, blue coloured bead formed is largely due to

A
$$\mathrm{B}_{2} \mathrm{O}_{3}$$
B
$$\mathrm{Co}\left(\mathrm{BO}_{2}\right)_{2}$$
C
$$\mathrm{CoB}_{4} \mathrm{O}_{7}$$
D
$$\mathrm{Co}\left[\mathrm{B}_{4} \mathrm{O}_{5}(\mathrm{OH})_{4}\right]$$
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