(English Medium) ICSE Class 10 - CISCE Important Questions for Chemistry

A gaseous hydrocarbon contains 82.76% of carbon. Given that its vapor density is 29, find its molecular formula. [C = 12, H = 11]

If the empirical formula of a compound is CH and it has a vapor density of 13, find the molecular formula of the compound.

Consider the following reaction and based on the reaction answer the questions that follow:

Calculate:

1) the quantity in moles of (NH₄)₂Cr₂O₇ if 63gm of(NH₄)₂Cr₂O₇ is heated.

2) the quantity in moles of nitrogen formed.

3) the volume in liters or dm3 of N2 evolved at S.T.P.

4) the mass in grams of Cr2O3 formed at the same time

(Atomic masses: H=1, Cr= 52, N=14]

A compound made up of two elements X and Y has an empirical formula X₂Y. If the atomic weight of X is 10 and that of Y is 5 and the compound ha a vapor density 25, find its molecular formula.

Ethane burns in oxygen to form CO₂ and H₂O according to the equation:

`2C_2H_6+7O_2 -> 4CO_2 + 6H_2O`

If 1250 cc of oxygen is burnt with 300 cc of ethane.

Calculate:

1) the volume of `CO_2` formed

2) the volume of unused `O_2`

 Give the appropriate term defined by the statements given below : 
The formula that represents the simplest ratio of the various elements present in one molecule of the compound. 

 Find the empirical formula and the molecular formula of an organic compound from the data given below : 
C = 75.92%, H = 6.32% and N = 17.76%
The vapour density of the compound is 39.5.
[C = 12, H = 1, N = 14]

The Empirical formula of an organic compound is CHCl₂.

If its relative molecular mass is 168, what is its molecular formula?

[At. Wt. C = 12, H = 1, Cl = 35.5]

Calculate:

Write the empirical formula of C₈H₁₈.

Pratik heated 11.2 grams of element ‘M’ (atomic weight 56) with 4.8 grams of element 'N' (atomic weight 16) to form a compound. Find the empirical formula of the compound obtained by Pratik.

Identify the substance underlined, in the following case

The electrolyte used for electroplating an article with silver.

Select the ion in the following case, that would get selectively discharged from the aqueous mixture of the ions listed below:

\[\ce{SO^2-_4, NO^-_3 {and} OH-}\]

Select the ion in the following case, that would get selectively discharged from the aqueous mixture of the ions listed below:

Pb²⁺, Ag⁺ and Cu²⁺

Name the following :

The process of coating of iron with zinc

Name the metallic ions that should be present in the electrolyte when an article made of copper is to be electroplated with silver.

Give reasons why In the electroplating of an article with silver, the electrolyte sodium argentocyanide solution is preferred over silver nitrate solution.

State one relevant observation for the following:

At the anode when aqueous copper sulphate solution is electrolysed using copper electrodes.

Copy and complete the following table:

Choose the correct answer from the options given below:

The electrolyte used for electroplating an article with silver is

A. Silver nitrate solution

B. Silver cyanide solution

C. Sodium argentocyanide solution

D. Nickel sulfate solution

Give one word or phrase for the following:

Electrolytic deposition of a superior metal on a baser metal.