List of top Chemistry Questions

IV A group elements are called
Presence of 3 unpaired electrons in nitrogen can be explained by ____ principle.
The observed molecular weight of a 1:1 strong electrolyte is 117 g mol\(^{-1}\) as determined by the depression of freezing point method. Its theoretical molecular weight is 60 g mol\(^{-1}\). The percentage dissociation of the electrolyte is:
Thermal decomposition of a compound X follows first order kinetics. The initial concentration of X is 2 mol L\(^{-1}\). It decreased to 0.125 mol L\(^{-1}\) in one hour at 400K. What is the half-life period of the reaction at 400K? (log 2 = 0.3010)
At 400 K, an ideal gas is enclosed in a 0.5 m\(^3\) vessel at a pressure of 203 kPa. What is the change in temperature required (in K), if it occupies a volume of 0.2 m\(^3\) under a pressure of 304 kPa? (Nearest integer)

At 400 K, the following graph is obtained for \( x \) moles of an ideal gas. \( x \) is equal to (R = gas constant, P = pressure, V = volume)
 

The functional groups involved in the conversion of glucose to gluconic acid and gluconic acid to saccharic acid respectively are:
Which of the following statement is correct?
Among the oxides SiO\(_2\), SO\(_2\), Al\(_2\)O\(_3\), and P\(_2\)O\(_5\), the correct order of acidic strength is:
Given below are two statements
Statement - I: For isothermal irreversible change of an ideal gas, \[ q = -w = P_{\text{ext}}(V_{\text{final}} - V_{\text{initial}}) \] Statement - II: For adiabatic change, \[ \Delta U = W_{\text{adiabatic}} \] The correct answer is:
Compound ‘X’ (C\(_6\)H\(_6\)O) reacts with aqueous NaOH to give compound ‘Y’. ‘Y’ reacts with CO\(_2\) followed by acidification to give compound ‘Z’. The compounds X, Y and Z are respectively
The bond order of \( O_2 \) molecule and its magnetic property are respectively:
Enthalpy of combustion of ethylene gas at constant pressure of 1 atm and at 300 K is -1410 kJ mol\(^{-1}\). The enthalpy change for the reaction at constant volume and at the same temperature is about (R = 8.3 J K\(^{-1}\) mol\(^{-1}\)):

The following results were obtained in the gas phase reaction between nitric oxide and oxygen at a given temperature.

What is the mass of crystalline oxalic acid (molar mass = 126 g/mol) present in 50 mL of 0.02N aqueous oxalic acid solution?
The critical temperature of A, B, C, D gases are 190 K, 630 K, 261 K, 400 K respectively. The quantity of gas adsorbed per gram of charcoal at same pressure is least for the gas
At 300 K, the vapour pressures of A and B liquids are 500 and 400 mm Hg respectively. Equal moles of A and B are mixed to form an ideal solution. The mole fraction of A and B in vapor state is respectively.
A compound is formed by atoms of A, B and C. Atoms of C form hcp lattice. Atoms of A occupy 50% of octahedral voids and atoms of B occupy $\frac{2}{3}$ of tetrahedral voids. What is the molecular formula of the solid?
Which of the following are the conditions for a reaction spontaneous at all temperatures?

Arrange the following halides in decreasing order of their reactivity towards dehydrohalogenation: 

The wavelength of an electron is \( 10^3 \) nm. What is its momentum in kg m s\(^{-1}\)?

Consider the reaction: \(C_2H_5Cl(g) \rightarrow 2C(g) + 5H(g) + Cl(g)\), where \(\Delta H = 3047 \, {kJ mol}^{-1}\). The bond dissociation enthalpy (\(\Delta_{{bond}} H\)) values of C–Cl and C=C bonds are 431 and 414 kJ mol\(^{-1}\), respectively. What is the average bond enthalpy of C–H in kJ mol\(^{-1}\)?
If the first ionisation enthalpy of Li, Be and C respectively are 520, 899, 1086 kJ/mol, the first ionisation enthalpy (in kJ/mol) of B will be

The vapour pressure of H\(_2\)O at 323K is 95 mm of Hg. 176g of sucrose (Molar mass = 342 gmol\(^{-1}\)) is added to 900g of H\(_2\)O at 323K. 
The vapour pressure of solution is about

When n-hexane is heated to 773K at 10-20 atmosphere pressure in the presence of \(Cr_2O_3\), benzene is formed. This reaction is called