Some Basic Concepts of Chemistry

4.08 g of a mixture of BaO and an unknown carbonate MCO3 was heated strongly. The residue weighed 3.64 g. This was dissolved in 100 ml of 1 N HCl. The excess acid required 16 ml of 2.5 N NaOH solution for complete neutralization. Identify t...

The density of a 3 M Sodium thiosulphate solution (Na2S2O3) is 1.25 g per ml. Calculate (i) the percentage by weight of sodium thiosulphate, (ii) the mole fraction of sodium thiosulphate and (iii) the molalities of Na+ and \(S_2O_3^{-2}\) ...

3 g of a salt of molecular weight 30 is dissolved in 250 g of water. The molality if the solution is _____.

Hydroxylamine reduces iron (III) according to the equation:
2NH2OH + 4Fe3+ \(\to\) N2O(g) \(\uparrow\) + H2O + 4Fe2+ + 4H+
Iron (II) thus produced is estimated by titration with a standard permanganate solution. The reaction is :
$$MnO_...

If 0.50 mol of BaCl2 is mixed with 0.20 mol of Na3PO4, the maximum amount of Ba3(PO4)2 that can be formed is

A 1.00 gm sample of H2O2 solution containing X percent H2O2 by weight requires X ml of a KMnO4 solution for complete oxidation under acidic conditions. Calculate the normality of the KMnO4 solution.

(i). A sample of MnSO4.4H2O is strongly heated in air. The residue is Mn3O4.
(ii). The residue is dissolved in 100 ml of 0.1N FeSO4 containing dilute H2SO4.
(iii). The solution reacts completely with 50 ml of KMnO4 solution.
(iv). 25 ml of ...

The modern atomic unit is based on the mass of ______.

(a) 1 litre of a mixture of CO and CO2
is taken. This
mixture is passed through a tube containing red hot
charcoal. The volume now becomes 1.6 litre. The
volumes are measured under the same conditions.
Find the composition of the mixture b...

Find
(i) The total number of neutrons and
(ii) The total mass of neutron in 7 mg of 14C
(Assume that mass of neutron = mass of hydrogen atom)

A mixture contains NaCl and unknown chloride MCl.
(i) 1g of this is dissolved in water. Excess of acidified AgNO3 solution is added to it. 2.567 g of white ppt is formed.
(ii) 1 g of original mixture is heated to 300oC. Some vapours come ou...

(a) One litre of a sample of hard water contains 1 mg of CaCl2 and 1 mg of MgCl2. Find the total hardness in terms of parts of CaCO3 per 106 parts of water by weight.
(b) A sample of hard water contains 20 mg of Ca++ ions per litre. How man...

The total no of electron present in 18 ml of water is ______.

A hydrocarbon contains 10.5 g of carbon per gram of hydrogen. 1 litre of the hydrocarbon at 127oC and 1 atmosphere weighs 2.8 g. Find the molecular formula.

A gaseous mixture contains oxygen and nitrogen in the ratio of 1 : 4 by weight. Therefore the ratio of their no of molecules is

2.76 g of silver carbonate on being strongly heated yields a residue weighing

In the analysis of 0.5 g sample feldspar, a mixture of chlorides of sodium and potassium is obtained which weighs 0.1180g. Subsequent treatment of mixed chlorides with silver nitrate gives 0.2451 g of silver chloride. What is the percentage...

Account for the following : Limit your answer to two
sentences.
"Atomic weights of most of the elements are fractional."

(a). 5.5 g of a mixture FeSO4.7H2O and Fe2(SO4)3.9H2O requires 5.4 ml of 0.1 N KMnO4 solution for complete oxidation. Calculate the number of gram mole of hydrated ferric sulphate in the mixture.
(b). The vapour density (hydrogen = 1) of a ...

The largest number of molecules is in

5 ml of a gas containing only carbon and hydrogen were mixed with an excess of oxygen (30 ml) and the mixture exploded by means of an electric spark. After the explosion, the volume of the mixed gases remaining was 25 ml. On adding a concen...

The total number of electrons is one molecule of carbon dioxide is

4.215 g of a metallic carbonate was heated in a hard glass tube and the CO2 evolved was found to measure 1336 ml at 27oC and 700 mm pressure. What is the equivalent weight of metal?

A compound was found to contain nitrogen and oxygen in the ratio 28 gm and 80 gm respectively. The formula of compound is

27 g of Al will react completely with how many grams if oxygen?

Igniting MnO2 converts it quantitatively to Mn3O4. A sample of pyrolusite is of the following composition : MnO2 80%, SiO2 and other inert constituents 15%, rest being water. The sample is ignited in air to constant weight. What is the perc...

Naturally occurring boron consists of two isotopes whose atomic weighs are 10.01 and 11.01. The atomic weight of natural oron is 10.81. Calculate the percentage of each isotope in natural boron.

One gram of an alloy of aluminium and magnetism when treated with excess of dil. HCl forms magnesium chloride, aluminium chloride and hydrogen. The evolved hydrogen, collected over mercury at \({0^o}C\) has a volume of 1.20 litres at 0.92 ...

What is the molarity and molality of a 13% solution (by weight) of sulphuric acid with a density of 1.02 g/ml? To what volume should 100 ml of this acid be diluted in order to prepare a 1.5 N solution?

What weight of AgCl will be precipitated when a solution containing 4.77 g of NaCl is added to a solution of 5.77g of AgNO3?