List of top Chemistry Questions

At a certain temperature, the vapour pressures of benzene and toluene are 119 torr and 37 torr, respectively. The mole fraction of toluene in the vapour phase, which is in equilibrium with a solution of benzene and toluene in 1 : 1 molar ratio, is

Which of the following statements are correct with respect to the unit of radioactivity?(i) The SI unit of radioactivity is curie [Ci].(ii) 1 Ci = 3.7 x 10^-10 dps(iii) 1 Bq = 3.7 x 10^-10 Ci(iv) The SI unit of radioactivity is becquerel (Bq).(v) 1 Ci = 3.7 x 10¹⁰ Bq

The coordination number of Ni²⁺ is 4.NiCI2 + KCN (excess) → A (cyano complex)A + conc. HCI (excess) → B (chloro complex)The IUPAC names of A and B, respectively, are

Which statement is incorrect 

The following graph shows how T1/2(half-life) of a reactant R changes with the initial reactant concentration a0.

The order of the reaction will be : 

For the reaction $S{O}_2+\frac{1}{2}{O}_2=S{O}_3,$ if we write $K_p=K_c(RT{)}^x,$ then $x$ becomes

Under which of the following condition is the relation valid $\mathrm{\Delta }H=\mathrm{\Delta }E+P\mathrm{\Delta }V$ for a closed system?

Hybridisation of central atom in NF3 is 

For the Paschen series the values of n1 and n2 in the expression $$\mathrm{\Delta }E=Rhc(\frac{1}{n_1^2}-\frac{1}{n_2^2})$$

Equal volumes of molar hydrochloric acid and sulphuric acid are neutralised by dilute NaOH solution and x kcal and y kcal of heat are liberated respectively.  Which of the following is true?

The time taken for 10% completion of a first order reactin is 20 mins. Then, for 19%  completion, the reaction will take 

A solution containing 30 g of non-volatile solute exactly in 90 g of water has a vapour pressure of 2.8 kPa at 298 K. Further, 18 g of water is then added to the solution and the new vapour pressure becomes 2.9 Pa at 298 K. Calculate:
(i) molar mass of the solute 
(ii) vapour pressure of water at 298 K.

Which of the following is not a thermodynamic coordinate?

The correct name of $\left[Pt{\left(N{H}_3\right)}_{4}C{l}_2\right]\left[PtC{l}_4\right]$ is:

Phenyl methyl ether (anisole) reacts with $HI$ to give phenol and methyl iodide and not iodobenzene and methyl alcohol because

The organic halogen compound used as refrigerant in refrigerators and air-conditioners is

Among the following compounds the one that is most reactive towards electrophilic nitration is :

Butene-1 may be converted to butane by reaction with

Which one of the following ions forms most stable complex compound?

In which of the following, functional group isomerism is not possible?

Which of the following cannot work as oxidizing agent ?

The correct order of reactivity of the halides, ethyl chloride $(I)$, isopropyl chloride $(II)$ and benzyl chloride $(III)$ in $S_N1$ reaction is

Among the following molecules: $SO_2,SF_4,ClF_3, BrF_5$ and $XeF_4$, which of the following shapes does not describe any of the molecules mentioned?

In the electrolysis of water, one faraday of electrical energy would evolve at STP

At temperature 300 K for reaction  C2H4(g) + 3O2(g)→ 2CO2(g) + 2H2O(g); ΔH = −336.2 kcal.  The approximate value of ΔU  at 300 K for the same reaction (R = 2 cal degree^{− 1} mol^{− 1}) will be-