List of top Chemistry Questions

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.
Cite the name of the enzyme responsible for the following biochemical transformation: \[ C_6H_{12}O_6 (\text{Glucose}) \xrightarrow{\text{Enzyme}} 2C_2H_5OH + 2CO_2 (\text{Ethanol}) \]
An aqueous HCl solution has the pH = 5. If 1 ml of this solution is being diluted to 1 L, then predict the pH of the resulting solution.
1 molal NaCl solution has the density 1.21 gm/cc. Find the molar concentration of the same solution.
At 12°C and 756 mm atmospheric pressure, a balloon contains 450 ml air. If the balloon is shifted to a place of temperature 5°C and atmospheric pressure 765 mm, then indicate the nature (shape) and degree (volume) of change of the balloon.
At 30°C, a substance being dissolved in CCl$_4$ (solvent) exhibits its dissociation half-life as 2.5 hrs. If 256 g of the substance is taken initially, then tell how much of it will remain as such after 20 hrs.
In HF molecule, internuclear distance is 0.92 Å and dipole moment approximates 2 D. Estimate the percentage ionic character of HF molecule.
First ionisation potential energy of Li(m) is 520 kJ/mol$^{-1}$, hence calculate the energy required to convert Li-atoms present in 70 mg Li(m) into Li$^+$ ion.

Identify the product(s) of the following two reactions (i) and (ii):

How would you differentiate between $ \text{O}_3 $ and $ \text{H}_2\text{O}_2 $ (chemically)?
In solid state, nitrogen exists in two different allotropic forms ($\alpha$ and $\beta$). Give an idea regarding their shapes and stability.

Ascertain the products $B_1$ and $C_1$ of the following reaction:

Analyzing the following reaction, ascertain the final product:

Write the end product of the following reaction:

Upon addition of phenolphthalein to the aqueous solution of borax, pink colour generates i.e. solution becomes pink. At this stage, if glycerol is being added to the pink coloured solution, it turns colourless. Highlight the phenomenon.
In aqueous medium, cations like $ \text{H}^+ $ and $ \text{Li}^+ $ undergo hydration and exist in the hydrated form. Predict the numbers of water molecules surrounded with $ \text{H}^+ $ and $ \text{Li}^+ $ ions to form stable complex structure respectively.
In the contact process of manufacturing \(\text{H}_2\text{SO}_4\), the arsenic purifier used in the industrial plant contains:
Trans-esterification is a reaction between