Some basic concepts of chemistry practice · Mixed difficulty

Assertion ($A$) Significant figures for 0.200 is 3 whereas for 200 it is 1. Reason ($R$) Zero at the end or right of a number are significant provided they are not on the right side of the decimal point.

The number of moles of $KMn{O_4}$ that will be needed to react completely with one mole of oxalate ion in acidic solution is

Vapour density of a gas is 32. Volume occupied by $16 \mathrm{~g}$ substance at S.T.P.

At $373 \mathrm{~K}$ and $1 \mathrm{~atm},$ if the density of liquid water is $1.0 \mathrm{~g} / \mathrm{ml}$ and that of water vapour is $0.0006 \mathrm{~g} / \mathrm{ml},$ then the volume occupied by water molecules in 1 litre of steam at that temperature is

A sample of ammonium phosphate ${\left( {N{H_4}} \right)_3}P{O_4}$ contains 6.36 moles of hydrogen atoms. The number of moles of oxygen atom in the sample is (atomic mass of N = 14.04, H = 1, P = 31, O = 16)

Statement-I: Equivalent weight of ${NH}_3,$ in the reaction $N_2 \rightarrow N H_3$ is $17 / 3$ while that of $N_2$ is $28 / 6.$

Statement-II: Equivalent weight $=\frac{\text { Molecular weight }}{\text { number of } e^- \text{ lost or gained/mole }}$

A metal ${M}$ forms the sulphate $\mathrm{M}_2\left({SO}_4\right)_3$. A $0.6 \mathrm{~g}$ sample of the metal sulphate reacts with excess ${BaCl}_2$ to give $1.2 \mathrm{~g}\, {BaSO}_4$. What is the atomic weight of ${M}$ ?

(Atomic weights : ${S}=32, {Ba}=137$ )

An unknown compound $\mathrm{A}$ dissociates at $500^{\circ} \mathrm{C}$ to give products as follows $A(g) \rightleftarrows B(g)+C(g)+D(g)$ Vapour density of the equilibrium mixture is 50 when it dissociates to the extent to $10 \%$. What will be the molecular weight of compound A-

Which contains the same number of molecules as $16\,\mathrm{g}$ of oxygen?

20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0 g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample?
(Atomic weight: $Mg = 24$)

$3.92 \mathrm{~g} / \mathrm{lit}$ of a sample of ferrous ammonium sulphate reacts completely with $50 \mathrm{ml} \frac{\mathrm{N}}{10} \mathrm{KMnO}_4$ solution. The percentage purity of the sample is

Haemoglobin contains $4.6 \%$ of $Fe$ by weight, the approximate minimum molecular mass of haemoglobin will be

14 g of element X combine with 16 g of oxygen. On the basis of this information, which of the followings is a correct statement?

When $100 \mathrm{~g}$ of ethylene polymerizes to polyethylene according to equation of $n \mathrm{CH}_2=\mathrm{CH}_2 \rightarrow-\left(\mathrm{CH}_2-\mathrm{CH}_2\right)_n-.$ The weight of polyethylene produced will be

Chemistry was not studied for its own sake, rather it came up as a result of search for

D5W refers to one of the solutions used as an intravenous fluid. It is $5 \%$ by mass solution of dextrose, $\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6$ in water. The density of D5W is $1.08 \mathrm{~g} / \mathrm{ml}.$ The molarity of the solution is

$245 \mathrm{~g}$ impure sample of ${KClO}_3(\mathrm{~s})$ on heating gives $12 \mathrm{~g}\,\, {O}_2(\mathrm{~g})$ according to

$2 {KClO}_3(\mathrm{s}) \rightarrow 2 {KCl}(\mathrm{s})+3 {O}_2(\mathrm{g})$ Calculate $\%$ purity of sample?

In the following reaction, which choice has value twice that of the equivalent mass of the oxidizing agent?

$\mathrm{S}{\mathrm{O}_2} + {\mathrm{H}_2}\mathrm{O} \to 3\mathrm{S} + 2{\mathrm{H}_2}\mathrm{O}$

A gaseous mixture contains oxygen and nitrogen in the ratio of $1:4$ by weight. Therefore, the ratio of their number of molecules is:

Assertion (A): Molarity of a solution in liquid state depends upon temperature.
Reason (R): Volume of a solution is temperature independent entity.

What will be the volume of $C{O_2}$ at NTP obtained on heating 10 grams of (90 % pure) limestone

A mixture of $\mathrm{NaHC}_2 \mathrm{O}_4$ and $\mathrm{KHC}_2 \mathrm{O}_4 \cdot \mathrm{H}_2 \mathrm{C}_2 \mathrm{O}_4$ required equal volumes of $0.2 \mathrm{~N} \mathrm{~KMnO}_4$ and $0.12 \mathrm{~N} \mathrm{NaOH}$ separately. What is the molar ratio of $\mathrm{NaHC}_2 \mathrm{O}_4$ and $\mathrm{KHC}_2 \mathrm{O}_4 \cdot \mathrm{H}_2 \mathrm{C}_2 \mathrm{O}_4$ in the mixture?

$17 \mathrm{~g}$ of $\mathrm{H}_2 \mathrm{O}_2$ is present in $100 \mathrm{ml}$ an aqueous solution $10 \mathrm{ml}$ of this on decomposition at STP will produce $m \ell$ of $\mathrm{O}_2$ at STP?

The equivalent weight of $\mathrm{KI}{\mathrm{O}_3}$ in the reaction, $2\mathrm{Cr}{\left( {\mathrm{OH}} \right)_3} + \mathrm{O}{\mathrm{H}^ - } + \mathrm{KI}{\mathrm{O}_3} \to 2\mathrm{CrO}_4^{2 - } + 5{\mathrm{H}_2}\mathrm{O} + \mathrm{KI}$ is

One mole of $\mathrm{N}_2 \mathrm{H}_4$ loses 10 moles of electrons to form a new compound y. Assuming that all nitrogen appear in the new compound, what is the oxidation state of nitrogen in y (There is no change in the oxidation state of hydrogen)

At constant temperature for 1 mole of an ideal gas, if its pressure is decreased by $20 \%$ then its volume will be increased by

Which one of the following sets of compounds correctly illustrate the law of reciprocal proportions?

Oxidation number of carbon in carbon suboxide is :

$1.5276 \mathrm{~g}$ of $\mathrm{CdCl}_2$ was found to contain $0.9367 \mathrm{~g}$ of $\mathrm{Cd}$. The atomic mass of $\mathrm{Cd}$ is (to the nearest integer):

In an experiment 50 mL of 0.1 $M$ solution of a salt reacted with 25 mL of 0.1 $M$ solution of sodium sulphite. The half equation for the oxidation of $\mathrm{SO}_3^{2 - }\left( {aq} \right) + {\mathrm{H}_2}\mathrm{O}\left( l \right) \to \mathrm{SO}_4^{2 - }\left( {aq} \right) + 2{\mathrm{H}^ + }\left( {aq} \right) + 2{e^ - }$ If the oxidation number of metal in the salt was 3, what would be the new oxidation number of metal?