List of top Chemistry Questions

The Tyndall effect is observed only when the following conditions are satisfied:

(A) The diameter of the dispersed particle is much smaller than the wavelength of the light used.
(B) The diameter of the dispersed particle is not much smaller than the wavelength of the light used.
(C) The refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude.
(D) The refractive indices of the dispersed phase and the dispersion medium are almost similar in magnitude.

Which of the following is not correct about the adsorption?

A $\rightarrow$ P is a first-order reaction. At 27°C, the time taken for the completion of 20% of the reaction is $ t_1 $ min. The time taken for the completion of 80% of the reaction is $ t_2 $ min at the same temperature. What is the value of $ \frac{t_2}{t_1} $?

At 27 °C, the pH of 1 L of aqueous copper sulfate is 5.5. This solution was electrolyzed using two Pt electrodes for some time. What is the pH of remaining copper sulfate solution?

The molar depression constant of water ($K_f$) is 1.86 K kg mol$^{-1}$. What is the approximate $ \Delta H_{fus} $ (in kJ mol$^{-1}$) of water if it freezes at 273 K?

At 27 °C, $x \, g$ of $ \text{CaCl}_2 $ was dissolved in 2.5 L of water. The osmotic pressure of the resultant solution is 0.82 atm. What is $x$ in grams? (Given $i = 2.5$, $R = 0.082 \, \text{L atm mol}^{-1} \text{K}^{-1}$)

What are the reagents X and Y respectively used in the following reaction sequence to convert a nitrile to a methyl group?

Cumene on oxidation in the presence of air gives a compound X. This in the presence of dilute acid gives Y and Z. The total number of $ sp^2 $ carbons in Y and Z is:

What are X, Y and Z in the given reaction sequence?

The product of Finkelstein reaction X, is not used in which of the following named reaction?

Which of the following is insoluble in water?

Which of the following represents double stranded helix structure of DNA?

Which of the following polymer used in the manufacture of paints and lacquers?

Arrange the following in increasing order of their pK$_b$ values.

In Dumas method of nitrogen estimation, 0.14 g of an organic compound gave 22.4 mL of nitrogen at STP. The percentage of nitrogen in the compound is:

What kind of colloid particle would result if ($ \text{AgNO}_3 $) solution is being added to excess KI solution?

Calculate the EMF of the Galvanic cell: $ \text{Zn} | \text{Zn}^{2+}(1.0 M) \parallel \text{Cu}^{2+}(0.5 M) | \text{Cu} $ Given: $ E^\circ_{\text{Zn}^{2+}/\text{Zn}} = -0.763 \, \text{V} $ and $ E^\circ_{\text{Cu}^{2+}/\text{Cu}} = +0.350 \, \text{V} $

At 10°C, a urea solution has the osmotic pressure 500 mm of Hg. Now, if the solution is being diluted and the temperature is increased to 25°C, then osmotic pressure becomes 105.3 mm of Hg. Predict the degree of dilution of the urea solution.

Find the values of a, b, c, and d for the following redox equation: $ a\text{I}_2 + b\text{NO} + 4\text{H}_2\text{O} = c\text{HNO}_3 + d\text{HI} $

A solution contains 0.1 M $ \text{Mg}^{2+} $ ion. Indicate the optimum pH value so that $ \text{Mg(OH)}_2 $ can be precipitated from this solution ($ K_{\text{sp}}[\text{Mg(OH)}_2] = 1.0 \times 10^{-11} $).

At 27°C temperature and 770 mm pressure, 243 ml of a dry gas weighs 280 mg. Determine the molecular weight of the gas.

If energy of an electron in the first orbit is -13.6 eV, then predict the amount of energy required to transfer it to the fourth orbit.

Metal oxides of A(m) and B(m) are structurally similar. Atomic weight of A is 52 and vapor density of its chloride is 79. Oxide of B contains 47.1% oxygen. Considering the above data, calculate the atomic weight of B (in nearest whole number).

Explain the following nitration reaction:

SiF$_6^{2-}$ exists but CF$_6^{2-}$ does not. Offer reason.