List of top Chemistry Questions

The pair of metals refined by "vapour phase refining" is

$CuSO_4$ solution is electrolysed for $15$ minutes to deposit $0.4725\, g$ of copper at the cathode. The current in amperes requited is (Faraday = $96.500 \,C\,mol^{-1}$. atomic weight of copper = $63$)

The number of moles of solute present in the solutions of $I, II$ and $III$ is respectively I. $500 \,mL$ of $0.2\, M\, NaOH$ II. $200 \,mL$ of $0.1 \,N \,H _{2} SO _{4}$ II. $6 g$ of urea in $1 \,kg$ of water

Which one of the following has maximum number of hybrid orbitals ?

Observe the following molecules. $PCl_5, BrF_5, ClF_5, PF_5, ClF_3, XeF_4, XeF_2, IF_5 $ The number of molecules having square pyramidal geometry from the above is

The walls of a closed cubical box of edge $60\, cm$ are made of material of thickness $1\, mm$ and thermal conductivity $4 \times 10^{-4} \; cal \; s^{-1} \; cm^{-1} {^{\circ}C^{-1}}$. The interior of the box is maintained $1000 \; {^{\circ}C}$ above the outside temperature by a heater placed inside the box and connected across $400\, V\, DC$ supply. The resistance of the heater is

Acetic acid on heating with $ {NH_3}$ forms $A$. When $A$ reacts with $ {LiAlH_4}$ followed by hydrolysis gives $B$. When $B$ is heated with chloroform in $KOH$ medium gives $C$. What are $B$ and $C$ respectively?

Noble metals like gold and platinum are soluble in which of the following mixtures?

White phosphorus is heated with concentrated $NaOH$ in $CO _{2}$ atmosphere to form a gas $A$ and compound $B$. When $A$ is bubbled into aqueous $CuSO _{4}$ solution copper phosphide and $C$ are formed, $B$ and $C$ are respectively

Which one of the following is not present in the nitration mixture?

Which of the following is water-gas shift reaction?

Which of the following metals exist in liquid state duiing summer season?

$KO _{2}$, reacts with water to form $A, B$ and $C .$ $B$ forms $C$ when it reacts with iodine in basic medium. What are $B$ and $C$ respectively?

$KMnO _{4}$ oxidises $S _{2} O _{3}^{2-}$ to $SO _{4}^{2-}$ in medium $x$ and $NO^{-}_2$ to $NO^{-}_3$ in medium $y, x$ and $y$ are respectively

Which of the following reactions can be used to prepare diborane? I) $ {BF_3 + LiAlH_4 ->[ether]}$ II) $ {BF_3 + NaH ->[450 k]}$ III) $ {Na_2B_4O_7 + H_2O -> }$ IV) $ { NaBH_4 + I_2 ->}$

Which of the following are carbonate ores? l) Magnetite II) Kaolinite III) Siderite IV) Calamine

The reaction in which $\Delta H > \Delta U$ is

Which of the following orders are correct against the property given? I) dipole moment : $NF_3 > NH_3 >BF_3$ II) Covalent bond length : $C - O > N - O > O - H$ III) Bond order : $C_2 > B_2 > He_2$

The mass of AgCl precipitated when a solution containing 11.70 g of NaCl is added to a solution containing 3.4 g of AgNO3 is [Atomic mass of Ag = 108, Atomic mass of Na = 23]

The number of structural isomers for $ {C_6H_{14}}$ is

A non-volatile solute, ?A? tetramerises in water to the extent of 80%. 2.5 g of ?A? in 100 g of water, lowers the freezing point by 0.3 ?C. the molar mass of ? in mol L-1 is (Kf for water = 1.86 K kg mol-1)

Among the following, the main reactions occurring in blast furnace during extraction of iron from haematite are 1. $Fe_{2}O_{3} + 3CO \to 2Fe + 3CO_{2}$ 2. $FeO + SiO_{2} \to FeSiO_{3}$ 3. $Fe_{2}O_{3} + 3C \to 2Fe + 3CO$ 4. $CaO + SiO_{2} \to CaSiO_{3}$

An aqueous solution of CuSO4 is subjected to electrolysis using inert electrodes. The pH of the solution will

Cis-1, 4-polyisoprene is called

The number of moles of electron required to reduce 0.2 mole of Cr2O-27 to Cr+3