MCQ
The first element of rare–earth metals is
  • Cerium
  • B
    Actinium
  • C
    Uranium
  • D
    Lanthanum

Answer

Correct option: A.
Cerium
a
It’s Obvious

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

The decomposition reaction $2 N _2 O _5( g ) \xrightarrow{\Delta} 2 N _2 O _4( g )+ O _2( g )$ is started in a closed cylinder under isothermal isochoric condition at an initial pressure of $1 atm$. After $Y \times 10^3 s$, the pressure inside the cylinder is found to be $1.45 atm$. If the rate constant of the reaction is $5 \times 10^{-4} s ^{-1}$, assuming ideal gas behavior, the value of $Y$ is. . . . . . . .
Primary and secondary amines can be distinguished by
Which sequence represents the best synthesis of hexanal ?

$\underset{Hexanal}{\mathop{C{{H}_{3\text{ }}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}CH=O}}\,$

The reaction of $CH_3OC_2H_5$ with $HI$ gives
Which one of the following lanthanides exhibits $+2$ oxidation state with diamagnetic nature ? (Given $\mathrm{Z}$ for $\mathrm{Nd}=60, \mathrm{Yb}=70, \mathrm{La}=57, \mathrm{Ce}=58$ )
Match List $I$ with List $II$.

List I (Complex) List $II$ (Type of isomerism)
$A$. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5\left(\mathrm{NO}_2\right)\right] \mathrm{Cl}_2$ $I$. Solvate isomerism
$B$. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5\left(\mathrm{SO}_4\right)\right] \mathrm{Br}$ $II$. Linkage isomerism
$C$. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]\left[\mathrm{Cr}(\mathrm{CN})_6\right]$ $III$. Ionization isomerism
$D$. $\left[\mathrm{Co}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3$ $IV$. Coordination isomerism

Choose the correct answer from the options given below:

Match the reactions (in the given stoichiometry of the reactants) in List-$I$ with one of their products given in List-$II$ and choose the correct option.

List-$I$ List-$II$
$\mathrm{P}_2 \mathrm{O}_3+3 \mathrm{H}_2 \mathrm{O} \rightarrow$ $\mathrm{P}(\mathrm{O})\left(\mathrm{OCH}_3\right) \mathrm{Cl}_2$
$\mathrm{P}_4+3 \mathrm{NaOH}+3 \mathrm{H}_2 \mathrm{O} \rightarrow$ $\mathrm{H}_3 \mathrm{PO}_3$
$\mathrm{PCl}_5+\mathrm{CH}_3 \mathrm{COOH} \rightarrow$ $\mathrm{PH}_3$
$\mathrm{H}_3 \mathrm{PO}_2+2 \mathrm{H}_2 \mathrm{O}+4 \mathrm{AgNO}_3 \rightarrow$ $\mathrm{H}_3 \mathrm{PO}_4$

 

The order of the oxidation state of the phosphorus atom in $\mathrm{H}_3 \mathrm{PO}_2, \mathrm{H}_3 \mathrm{PO}_4, \mathrm{H}_3 \mathrm{PO}_3$, and $\mathrm{H}_4 \mathrm{P}_2 \mathrm{O}_6$ is
Match List $- I$ with List $- II.$

List $- I$

List $- II$

$(a)$ Zymase $(i)$ Stomach
$(b)$ Diastase $(ii)$ Yeast
$(c)$ Urease $(iii)$ Malt
$(d)$ Pepsin $(iv)$ Soyabean

Choose the correct answer from the options given below

A chemist wants to determine the molecular geometry of the $[CoCl_4]^{2-}$ ion. Which of the following gives the best suggestion for a measurement and for the interpretation of that measurement ?