Some Basic Concepts of Chemistry

A solid mixture weighing 5 g contains equal number of moles of $\mathrm{Na}_2 \mathrm{CO}_3$ and NaHCO . This solid mixture was dissolved in 1 L of water. What is the volume (in mL ) of 0.1 M HCl required to completely react with this 1 L m...

4.0 g of a mixture containing $\mathrm{Na}_2 \mathrm{CO}_3$ and $\mathrm{NaHCO}_3$ is heated to 673 K . Loss in mass of the mixture is found to be 0.62 g . The percentage of sodium carbonate in the mixture is

12 g of an element reacts with 32 g of oxygen. What is the equivalent weight of the element ?

The incorrect rule regarding the determination of significant figures is

0.43 g of a metal of valence 2 was dissolved in 50 mL of $0.5 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}$ solution. The unreacted acid required 14.2 mL of 1 M NaOH solution for neutralisation. The atomic weight of the metal is

Which one of the following has the same number of atoms as are in 6 g of $\mathrm{H}_2 \mathrm{O}$ ?

The masses of carbondioxide and water (in g) respectively formed during complete combustion of 10 g of glucose at STP are

The sum of three values $12.0,19.034$ and 2.0143 is equal to $X$. The number of significant figures in $X$ is

Magnetite can be reduced with CO to yield iron metal and carbon dioxide. Calculate the mass of magnetite (in kg ) needed to obtain 4 kg of iron if the process is $80 \%$ efficient. [Atomic weight of Fe and O are 56 g and 16 g , respectively...

Round the number 234555359 to 3 significant figure.

Identify the values of $a, b, c, d$ and $e$ for the following unbalanced reaction,
$$ \begin{aligned} a \mathrm{KNO}_3+5 \mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11} \longrightarrow b \mathrm{~N}_2 & +c \mathrm{CO}_2 +d \mathrm{H}_2 \ma...

The number of significant figures in 2.0400 is

The average molecular weight of the air which has $21 \%$ of $\mathrm{O}_2$ and $79 \%$ of $\mathrm{N}_2$, is

Combustion of 10 mL of a gaseous hydrocarbon gives 40 mL of $\mathrm{CO}_2$ and 50 mL of water vapour under the same conditions. The molecular formula of the hydrocarbon is

The amount of $50 \%(w / w)$ solution of hydrochloric acid required to react with 200 g of $\mathrm{CaCO}_3$ would be

Calculate the number of moles of NaOH required to completely neutralise 100 g of $118 \%$ oleum.

The molecular mass of sucrose $\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)$ is

Sulphuric acid reacts with sodium hydroxide as follows:
\(\mathrm{H}_2 \mathrm{SO}_4+2 \mathrm{NaOH} \longrightarrow \mathrm{Na}_2 \mathrm{SO}_4+2 \mathrm{H}_2 \mathrm{O}\)
What will be the amount of sodium sulphate formed, when l L of 0....

Given the ratio of amounts of nitrogen and oxygen in a particular gaseous mixture is $4: 1$. Calculate the ratio of number of their molecules?

For a given unbalanced reaction, $\mathrm{MnO}_2+\mathrm{HCl} \longrightarrow \mathrm{MnCl}_2+\mathrm{H}_2 \mathrm{O}$, which is the limiting reagent, if the initial amount for each of the reactant is 100 grams?
[Molar masses : $\mathrm{MnO...

The emperical formula of a compound is $\mathrm{C}_2 \mathrm{H}_5 \mathrm{O}$ and its vapour density is 45 . What is the molecular formula of the compound?

How much volume of 1 N aqueous solution of $\mathrm{H}_2 \mathrm{SO}_4$ should be taken, which will contain 0.2 moles of $\mathrm{H}_2 \mathrm{SO}_4$ ?

25 mL of 0.1 N NaOH solution neutralises 12.5 mL of HCl solution. The amount of water needed to convert 500 mL of such HCl solution to 0.1 N is

Identify the law for which the following statement is true.
"Equal volume of all gases at same temperature and pressure should contain equal number of molecules".