List of practice Questions

Give one relevant observation for the following: 

(a) Sodium hydroxide is added dropwise to Calcium nitrate solution. 
(b) Dilute Hydrochloric acid is added to Iron (II) sulphide. 
(c) An amphoteric metal is added to hot concentrated alkali. 
 

Study the reaction scheme shown below and identify the reactants A, B and C. 

 

5.6 litres of gas Z weighs 32 g at STP. What is the molecular weight and vapour density of Z?
Name the following:
(a) The most electronegative element of Period 2
(b) The largest atom of Period 3

K, L and M are beakers containing three different solutions: [Beaker K: Aqueous acetic acid, Beaker L: Sodium chloride solution, Beaker M: Distilled water]. Name the beaker which: 
(a) contains only ions. 
(b) contains only molecules. 
(c) has pH less than 7. 

 

Carbon reacts with an acid to form carbon dioxide, water and nitrogen dioxide.
(a) Name the acid used in the reaction.
(b) Write a balanced chemical equation for the reaction that occurs.
Given below are a few elements: Li, K, Cs, F.
Identify the element which:
(a) has the least atomic radius.
(b) has two valence electrons.
(c) is the most electropositive.
During the manufacture of sulphuric acid, a chemist collected the gas formed after catalytic oxidation of sulphur dioxide.
(a) Name the gas collected.
(b) Which acid is formed when the gas collected by the chemist is dissolved directly in water?
(c) Why should we not dissolve this gas directly in water?
Equal volumes of ammonia gas and chlorine gas are kept in two different containers under the same conditions of temperature and pressure. Find the number of molecules contained in chlorine gas when the mass of ammonia is 34 g. (Atomic weight: Cl = 35.5, H = 1, N = 14)
Elements P, Q, and R are in the same period of the modern periodic table.
• P readily loses its one valence electron to form a stable ion.
• Q shares its electrons in bonding but does not form ions easily.
• R has high electronegativity.
Alex was given a solution of an unknown salt Y for analysis. He performed the following tests and recorded his observations:
• To a part of the solution Y, he added silver nitrate solution and obtained a white precipitate which was soluble in ammonium hydroxide solution.
• To the remaining solution he added a few drops of sodium hydroxide solution and obtained a pale blue precipitate.
Based on the observations made by Alex, identify:
(a) the anion and
(b) the cation present in salt Y.
Study the reaction given below and answer the questions that follow:
NaNO₃ + H₂SO₄ → NaHSO₄ + HNO₃ (below 200°C)
(a) Give one reason for maintaining the temperature below 200°C.
(b) Why is concentrated Sulphuric acid used in the above reaction?
What volume of carbon dioxide is produced at STP when 5 litres of propane is burnt completely according to the equation given below?
[ C_3H_8 + 5O_2 3CO_2 + 4H_2O ]
The compound that has the highest melting point amongst the following is:
With respect to the electrolysis of copper (II) sulphate solution using copper electrodes, which statement is correct?
Following reaction takes place in one step :
\( 2A + B \rightarrow 2C \)
How will the rate of above reaction change if the volume of the reaction vessel is decreased to one third of its original volume? Will there be any change in the order of reaction with the reduced volume?
A point charge of \(10^{-8}\) C is placed at origin. The work done in moving a point charge 2 \(\mu\)C from point A(4, 4, 2) m to B(2, 2, 1) m is_______ J. (\(\frac{1}{4\pi\epsilon_0} = 9 \times 10^9\) in SI units)
In an A.P., \(15^{th}\) term exceeds the \(8^{th}\) term by 21. If sum of first 10 terms is 55, then form the A.P.
In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.
Complete the following: A substance whose resistance becomes almost negligible at a temperature near absolute zero is called a __________.
Complete the following:

1. Reactant: RCOCl
Reagent: H2 / Pd-BaSO4
Major Product: RCHO
Name of Reaction: Rosenmund Reduction

2. Reactant: CH3COOH
Reagent: Cl2 / Red P
Major Product: Cl-CH2COOH
Name of Reaction: HVZ Reaction

3. Reactant: CH3CHO
Reagent: Zn-Hg / conc. HCl
Major Product: CH3CH3
Name of Reaction: Clemmensen Reduction

(i)[Ni(CN)₄]²⁻ and [Ni(CO)(_4)] have different structures, but do not differ in their magnetic behaviour. Explain. 
(ii) Write the formula of Tetraamineaquachloridocobalt(III)chloride.

How do you prepare K₂Cr₂O₇ from chromite ore?

Give reasons for the following: 
(i) Zn, Cd and Hg are not considered transition elements. 
(ii) Transition metals form complex compounds. 
(iii) Sc(3+) is colourless, but Ti(3+) is coloured.

Briefly explain the electrochemical processes involved in the rusting of iron.