22506.(NH4)2Cr2O7 on heating gives a gas which is also given by
heating NH4NO2
heating NH4NO3
Mg3N2 + H2O
Na (comp.) + H2O2
22507.Knowing that the chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect?
The ionic sizes of Ln (III) decrease in general with increasing atomic number
Ln (III) compounds are generally colourless
Ln (III) hydroxides are mainly basic in character
Because of the large size of the Ln (III) ions the bonding in its compounds is predominantly ionic in character
22508.Which of the statements is not true?
K2Cr2O7 solution in acidic medium is orange
K2Cr2O7 solution becomes yellow on increasing the pH beyond 7
On passing H2S through acidified K2Cr2O7 solution, a milkycolour is observed
Na2Cr2O7 is preferred over K2Cr2O7 in volumetric analysis
22509.During the extraction of gold the following reactions take place
Au + CN– + H2O $\xrightarrow{O_2}$ [X]
[X] + Zn → [Y] + Au
X and Y are respectively
[Au(CN)2]– and [ZN(CN)4]2–
[Au(CN)4]3– and [ZN(CN)4]2–
[Au(CN)4]2– and [ZN(CN)4]2–
[Au(CN)2]– and [ZN(CN)6]4–
22511.Identify the incorrect statement among the following
d–Block elements show irregular and erratic chemical properties among themselves
La and Lu have partially filled d orbitals and no other partially filled orbitals
The chemistry of various lanthanoids is very similar
4f and 5f orbitals are equally shielded
22513.Which of the following types of metals form the most efficient catalysts?
alkali metals
alkaline earth metals
transition metals
all the above