List of top Chemistry Questions

Identify the set of molecules which act as bleaching agents only by oxidation
Which of the following is used in liquid detergents?
The set of complex ions having the same number of unpaired electrons is
The hybridisation of the central atom of \( BF_3 \), \( SnCl_2 \), \( HgCl_2 \), respectively is?

In the following reaction sequence, what are X and Y respectively? 

 

Match the following:
 


The correct answer is:
 

At 300 K, the vapour pressure of liquids A and B are 600 and 500 mm of Hg respectively. Two moles of A and three moles of B are mixed. The mole fractions of A and B in vapor state are respectively
The common components of photochemical smog are:
Observe the following species: (i) \( NH_3 \) (ii) \( AlCl_3 \) (iii) \( SnCl_4 \) (iv) \( CO_2 \) (v) \( Ag^+ \) (vi) \( HSO_4^- \) How many of the above species act as Lewis acids?
Identify the correct statements from the following: (i) Ti (IV) is more stable than Ti (III) and Ti (II)
(ii) Among 3d-series elements (from Z = 22 to 29) only copper has positive reduction potential (\( M^{2+}/M \)) (iii) Both Sc and Zn exhibit +1 oxidation state
An open vessel containing air was heated from 27°C to 727°C. Some air was expelled. What is the fraction of air remaining in the vessel? (Assume air as an ideal gas)
Distilled water boils at 373.15 K and freezes at 273.15 K. A solution of glucose in distilled water boils at 373.202 K. What is the freezing point (in K) of the same solution? (For water, \( K_b = 0.52 \) kg mol\(^{-1}\), \( K_f = 1.86 \) kg mol\(^{-1}\))
Among the oxides SiO\(_2\), SO\(_2\), Al\(_2\)O\(_3\), and P\(_2\)O\(_5\), the correct order of acidic strength is:
In the following reaction: \[ \text{C} + \text{Conc.} \, \text{H}_2\text{SO}_4 \xrightarrow{\Delta} \text{X} + \text{Y} + \text{H}_2\text{O} \] X and Y in the above reaction are:

The set of elements which obey the general electronic configuration \( (n-1)d^{10} ns^2 \) is:}

Which among the following oxoacids of phosphorus will have P-O-P bonds?

I. H4P2O5

II. H4P2O6

III. H4P2O7

IV. (HPO3)3

 

At T(K), \( K_c \) for the dissociation of \( PCl_5 \) is \( 2 \times 10^{-2} \) mol L\(^{-1}\). The number of moles of \( PCl_5 \) that must be taken in 1.0 L flask at the same temperature to get 0.2 mol of chlorine at equilibrium is
Which of the following does not evolve \( O_2 \) when made to react with water?
Kaolinite is a silicate mineral of metal 'X' and calamine is a carbonate mineral of metal 'Y'. X and Y respectively are:
Observe the following reaction: \[ xI^- + y \, \, MnO_4^- + z \, H^+ \rightarrow a \, Mn^{2+} + b \, H_2O + cl_2 \] Which of the following are correct?
The oxygen carrying capacity of blood is reduced due to binding of haemoglobin with
Two statements are given below. Statement I: Adsorption of a gas on the surface of charcoal is primarily an exothermic process.
Statement II: A closed vessel containing \( O_2(g) \), \( H_2(g) \), \( Cl_2(g) \), \( NH_3(g) \) has a pressure of 9 atm. About 1 g of charcoal was added to this vessel and after some time its pressure is \( P' \) atm. It is observed that \( P'>P \). Choose the correct answer.
An alkene ‘X’ (C\(_4\)H\(_8\)) does not exhibit cis/trans isomerism. Reaction of ‘X’ with Br\(_2\)/CCL\(_4\), followed by reaction with reagent ‘Y’ gave ‘Z’ (C\(_6\)H\(_6\)). What are ‘Y’ and ‘Z’ respectively?
The wavenumber of the first spectral line of the Lyman series of He\(^+\) ion is \( x \) m\(^{-1}\). What is the wavenumber (in m\(^{-1}\)) of the second spectral line of the Balmer series of Li\(^{2+}\) ion?
The first ionization enthalpies of the elements X, Y, Z of the second period are 899, 1402, 520 kJ/mol respectively. X, Y, Z respectively are: