Some basic concepts of chemistry practice · Mixed difficulty

The mass of 2.5 g.atom of oxygen is

Statement - I: For reaction: $2A(g) + 3B(g) \rightarrow 4C(g) + D(g),$ the vapour density remain
constant throughout the progress of reaction.

Statement - II: In all the gaseous chemical reactions, the vapour density remains constant.

Which has minimum number of atoms of oxygen ?

Rearrange the following (I to IV) in the order of increasing masses and choose the correct answer from (1), (2), (3) and (4) (Atomic mass: $N=14, O=16, C u=63$).

I. 1 molecule of oxygen

II. 1 atom of nitrogen

III. $1 \times 10^{-10} \mathrm{~g}$ molecular weight of oxygen

IV. $1 \times 10^{-10} \mathrm{~g}$ atomic weight of copper

Assertion (A): A one molal solution prepared at $20^{\circ} \mathrm{C}$ will retain the same molality at $100^{\circ} \mathrm{C},$ provided there is no loss of solute or solvent on heating.

Reason (R): Molality is independent of temperature.

A nitrogen containing organic compound contain 28.9% nitrogen by weight. If one molecule compound have 4 nitrogen atom then molecular weight of compound is:

The mass of $\mathrm{112}\;\mathrm{c}{\mathrm{m}^3}\;\mathrm{C}{\mathrm{H}_4}$ gas a STP is

How many litres of detonating gas may be produced at $0^{\circ} \mathrm{C}$ and $1 \mathrm{~atm}$ from the decomposition of 0.1 mole of water by an electric current?

Which has the maximum number of atoms?

$0.72 \mathrm{~gm}$ of an oxide of a metal $\mathrm{M}$ on reduction with $\mathrm{H}_2$ gave $0.64 \mathrm{~g}$ of the metal. The atomic weight of the metal is 64. The empirical formula of the compound is

Volume occupied by $3.01 \times {10^{23}}\;\;$ molecules of acetylene at NTP is:

Molecular weight of tribasic acid is W. Its equivalent weight will be:

How many gram of $\mathrm{NaOH}$ will be required to neutralize $12.2 \mathrm{~g}$ benzoic acid?

The correctly reported answer of addition of 29.4406, 3.2 and 2.25 will have significant figures

The significant figures in 3400 are

Which of the following statements is correct about the reaction given below?

$4 \mathrm{Fe}(\mathrm{s})+3 \mathrm{O}_2(\mathrm{~g}) \longrightarrow 2 \mathrm{Fe}_2 \mathrm{O}_3(\mathrm{~g})$

Number of atoms in 558.5 g of Fe is (at . wt = 55.85)

Assertion: Density is expressed as $\mathrm{g} \mathrm{~mL}^{-1}$ whereas specific gravity is dimensionless.
Reason: Specific gravity is ratio of the masses of solution and solvent.

$25 \mathrm{~ml}$ solution containing $\left(6.35 \mathrm{~g} / \mathrm{L}\right.$ of $\mathrm{K} \mathrm{H}_3\left(\mathrm{C}_2 \mathrm{O}_4\right)_2 \cdot 2 \mathrm{H}_2 \mathrm{O}$ required $\mathrm{V}_1 \mathrm{ml}$ of $0.1 \mathrm{~N}$ $\mathrm{NaOH}$ and $\mathrm{V}_2 \mathrm{ml}$ of $0.1 \mathrm{~N} \mathrm{~KMnO}_4$ in two separate titrations. Calculate $\mathrm{V}_1$ and $\mathrm{V}_2$.
$\mathrm{KH}_3\left(\mathrm{C}_2 \mathrm{O}_4\right)_2 \cdot 2 \mathrm{H}_2 \mathrm{O} ; \mathrm{M}_0=254 \mathrm{~gm} / \mathrm{mol}$

Sodium bicarbonate $\mathrm{NaHCO}_3$ can be purified by dissolving it in hot water $\left(60^{\circ} \mathrm{C}\right),$ filtering to remove insoluble impurities, cooling to $0^{\circ} \mathrm{C}$ to precipitate solid $\mathrm{NaHCO}_3,$ and then filtering to remove the solid, leaving soluble impurities in solution. Any $\mathrm{NaHCO}_3$ that remains in the solution is not recovered. The solubility of $\mathrm{NaHCO}_3$ in hot water at $60^{\circ} \mathrm{C}$ is $164 \mathrm{~g} /$ litre and is $69 \mathrm{~g/litre}$ in cold water at $0^{\circ} \mathrm{C}.$ What is the percentage yield of $\mathrm{NaHCO}_3,$ when it is purified by this method?

One $\mathrm{g}$ of impure $\mathrm{Na}_2 \mathrm{CO}_3$ is dissolved in water and the solution is made upto $250 \mathrm{~mL}$. To $50 \mathrm{~mL}$ of this made up solution, $50 \mathrm{~mL}$ of $0.1 \mathrm{~N} \mathrm{~HCl}$ is added and the mixture after shaking well required $10 \mathrm{~mL}$ of $0.16 \mathrm{~N}$ sodium hydroxide solution for complete neutralization. Calculate the per cent purity of the sample of $\mathrm{Na}_2 \mathrm{CO}_3$.

$\mathrm{NaClO}$ solution reacts with ${\mathrm{H}_2}\mathrm{S}{\mathrm{O}_3},as,\mathrm{NaClO} + {\mathrm{H}_2}\mathrm{S}{\mathrm{O}_3} \to \mathrm{NaCl} + {\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4}$ A solution of $\mathrm{NaClO}$ used in the above reaction contained 15 g of $\mathrm{NaClO}$ per litre. The normality of the solution would be :

In a gaseous reaction of the type $aA + bB \to cC + dD,$ which is wrong?

Which of the following statements illustrate the law of multiple proportions?

A 0.518 g sample of lime stone is dissolved in $HCl$ and then the calcium is precipitated as $\mathrm{Ca}{\mathrm{C}_2}{\mathrm{O}_4}$. After filtering and washing the precipitate, it requires 40.0 mL of $0.250N\mathrm{KMn}{\mathrm{O}_4},$, solution acidified with ${\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4}$ to titrate is as, $\mathrm{MnO}_4^ - + {\mathrm{H}^ + } + {\mathrm{C}_2}\mathrm{O}_4^{2 - } \to \mathrm{M}{\mathrm{n}^{2 + }} + \mathrm{C}{\mathrm{O}_2} + 2{\mathrm{H}_2}\mathrm{O}$. The percentage of $\mathrm{CaO}$ in the sample is :

In redox reaction, ${H}_2 {O}_2$ oxidises ${K}_4\left[{Fe}({CN})_6\right]$ into ${K}^{+}, {Fe}^{+3}, {CO}_3{ }^{-2}$ and ${NO}_3^-$ ions in acidic medium, than how many moles of ${H}_2 {O}_2$ will react with 1mole of ${K}_4\left[{Fe}({CN})_6\right]$

Number of gas molecules present in $1 \mathrm{~ml}$ of gas at $0^{\circ} \mathrm{C}$ and $1 \mathrm{~atm}$ is called Loschmidt number. Its value is about

Calculate the molality of 1 litre solution of $93 \% \, \mathrm{H}_2 \mathrm{SO}_4$ (weight/volume). The density of the solution is $1.84 \mathrm{~g} / \mathrm{mL}$.

$100 \mathrm{~mL}$ of $2.4 \mathrm{~V} {~H}_2 {O}_2$ require how many grams of ${KMnO}_4$ in acidic medium for complete reaction?

A sample of nitric acid is $69 \%$ by mass and it has a concentration of 15.44 moles per litre. Its density is