Colour

Q.

The colour of chlorine gas is ?

1. red

2. yellow

3. purple

4. orange

Q. The colour of $K_{2}C{r}_2{O}_7$ and $F{e}^{2+}$ ions are respectively due to:

1. d - d transition and charge transfer spectra
2. charge transfer spectra and d-d transition
3. crystal defects and charge transfer spectra
4. charge transfer spectra and crystal defects

Q. 12.53 ml of 0.051 M SeO2 reacted with 25.52 ml of 0.1M CrSO4 solution. In the reaction Cr+2 was oxidised to Cr+3 . The oxidation state at which selenium was converted is

Q. (2)which of the following statements is incorrect (1)aluminium reacts with excess NaOH to give AlOH_3 NAHCO_3 on heating gives Na_2CO_3 (3)Pure sodium dissolves in liquid ammonia to give blue solution (4NaOH reacts with glass to give sodium silicate

Q.

Which of the following sets includes only transition elements?

1. z = 11, 14, 22, 42

2. z = 13, 33, 54, 83

3. z = 24, 39, 74, 80

4. z = 19, 32, 51, 101

Q. Assign oxidation number to the underlined element in $KAl(\underset{–}{S}{O}_4{)}_2.12H_{2}O$

Q.

A sub-shell of $l$ has _____ angular nodes.

1. $l^2$

2. $l-1$

3. $l$

4. $2l$

Q. Which of the following complex ion is expected to absorb light in the visible region ?

Q. Write formulas for the following compounds.

Q. Which of the following statement(s) is/are true regarding defects in ionic solids?

1. Heating $NaCl$ in sodium vapour atmosphere produces impurity defect.
2. F-centres are created in Frenkel defect
3. Adding $SrC{l}_2$ to molten $NaCl$ produces impurity defect
4. Irregularity around a line is called line defects

Q.

The colour imparted by Cobalt (II) compounds to glass is:

1. Green

2. Deep blue

3. Yellow

4. Red

Q. oxidation state of oxygen in pottasium peroxid

Q.

why h2o2 act as a bleaching agent.?

Q. Colour of dipositive Lanthanum (II) cation is due to:

1. d-d transition

2. f-f transition

3. charge transfer

4. None of these

Q. How the oxidant state of MnO2 is +4? I have problem finding the oxidant state.

Q. Which one of the following when dissolved in water gives coloured solution in nitrogen atmosphere ?

JEE MAINS 2021

1. $CuC{l}_2$
2. $ZnC{l}_2$
3. $C{u}_{2}C{l}_2$
4. $AgCl$

Q. The pink colour of lithium chloride crystal is due to:

1. Impurity defect
2. Metal excess defect
3. Frenkel defect
4. Metal deficiency defect

Q. Solve this:
(a) Balance the following redox equation by oxidation numbers method. The reaction occur in acidic medium.
$H_2{O_2}_{\left(aq\right)}+C{r}_2{{O_7}^{2-}}_{\left(aq\right)\underset{}{\to }}{O_2}_{\left(aq\right)}+C{r^{3+}}_{\left(aq\right)}$
(b) Give uses of heavy water (D₂O)

Q. Consider the elements $Cs,Ne,I$ and $F$.

Q. Of the following outer electronic configurations of atoms, the highest oxidation state is achieved by which one of them

1. $(n-1)d^{3}n{s}^2$
2. $(n-1)d^{5}n{s}^1$
3. $(n-1)d^{8}n{s}^2$
4. $(n-1)d^{5}n{s}^2$