List of top Chemistry Questions

Statement-I : Test for nitrite; sulphanilic acid and 1-napthylamine are used.
Statement-II : Acidified nitrite is di-azotized with sulphanilic acid and coupled with 1-napthylamine.
Select the correct statement.
In $4^{\text{th}}$ period of periodic table the elements with the largest and smallest size respectively is :
The wave number of three spectral line of H-atom are given. The correct set of spectral lines belonging to Balmer series?
Calculate pH of 10 mM weak acid (HA) dissociated in water. Assume $\alpha$ to be negligible. Given $\text{pK}_a = 4$
Consider the following changes : $\text{SnO}_2 \rightarrow \text{SnO}$ $\Delta G_1^o$ and $\text{PbO}_2 \rightarrow \text{PbO}$ $\Delta G_2^o$. Select the correct option
The correct order of electron gain enthalpy (magnitude only) for group 16 elements is:
Element X is the lightest element of group 7 of periodic table which forms oxo-anion in +6 oxidation state. The colour of potassium salt of the oxo-anion is:
The half-life of radioactive isotope Zn$^{65}$ is 245 days. Find the time after which activity of Zn sample remains 75% of its initial value.
Correct order of 2$^{nd}$ ionisation energy is:
In general tests of Ba$^{2+}$ and Ca$^{2+}$ give the respective tests as:
Two moles each of the gases P$_2$, Q$_2$ and PQ are present in a vessel at equilibrium. If 1 mole each of P$_2$ and Q$_2$ is added at equilibrium, then determine the composition (in mole) of each species at the new equilibrium.
Select incorrect option:
0.18 M HQ solution has molar conductivity $\frac{1}{30}$ times the molar conductivity of 0.02 M HZ solution. Find the value of pK$_a$(HQ) − pK$_a$(HZ).
[Given that $\alpha$ is very less than 1]
Statement-I: Two different aldehydes on cross aldol condensation always give four products.
Statement-II: Among benzaldehyde and acetophenone, only acetophenone reacts with semicarbazide.
Statement-I: Sucrose is dextrorotatory and upon hydrolysis, it becomes laevorotatory. Statement-II: Sucrose on hydrolysis gives glucose and fructose such that the laevorotation of glucose is more than dextrorotation of fructose. Which of the following is correct?
Which of the following statement is correct regarding an element having atomic number 79?
Sodium extract of organic compound of 0.1 g is treated with chlorine water and \( \text{CCl}_4 \) which dissolves in organic solvent to produce a violet colour. Upon treatment with \( \text{AgNO}_3 \), a yellow ppt. of 0.12 g is produced. Calculate the percentage of halide in the organic compound.
Which of the following statement is correct regarding the nature and directive influence of \( \text{NO}_2 \) group in nitrobenzene?
25 ml, 0.1 M Ba(OH)$_2$ react completely with HCl. Find the weight of HCl (in milligram) required?
The maximum number of electrons in the following two given set of quantum numbers (i) \( n = 5, \, m_l = -1 \) and (ii) \( n = 4, \, \ell = 2, \, m_l = 1, \, m_s = \frac{1}{2} \) respectively is:
Which of the following are the compound(s) that do not give Tollen's test?
For a given reaction, K$_p$ = 9 atm
NH$_3$(g) $\longrightarrow$ $\frac{1}{2}$ N$_2$(g) + $\frac{3}{2}$ H$_2$(g)
Total pressure at equilibrium is $\sqrt{5}$ atm.
Find the value of 7$\alpha^2$, where $\alpha$ is degree of dissociation of NH$_3$(g)
Which of the following is correct match for hydrogen-like species for the total energy of e$^-$?
The correct order of ionization energy of Cl, S, P, Al, Si is:
Consider the following statements about group 13 elements of the periodic table. (A) Electronegativity decreases down the group.
(B) Size increases down the group.
(C) Ionization energy decreases down the group.
(D) Boiling point of Boron is maximum.
(E) Melting point of Boron is maximum.