List of practice Questions

The mean deviation from the median of the following set of observations 5, 3, 9, 12, 3, 10, 12, 21, 18, 12, 21 is
The mean marks of 120 students is 20. It was later discovered that two marks were wrongly taken as 50 and 80 instead of 15 and 18. The correct mean of marks is
The mean of $100$ observations is $50$ and their standard deviation is $5$. The sum of all squares of all the observations is
The mean of 12 numbers is 24. If 5 is added in every number, the new mean is
The mean of $5$ observations is $4.4$ and their variance is $8.24$. If three of the observations are $1$, $2$ and $6$, find the other two observations.
The mean of the first n terms of the A.P. (a + d) + (a + 3d) + (a + 5d) + .... is
The mean of the given data is $30$. If total data is $70$, then missing numbers are
The mean of two samples of size 200 and 300 were found to be 25, 10 respectively. Their standard deviations were 3 and 4 respectively. The variance of combined sample of size 500 is
The mean weight of a group of 10 items is 28 and that of another group of n items is 35. The mean of combined group of 10 + n items is found to be 30. The value of n is
The most stable measure of central tendency is
$0.92 \,g$ of an organic compound was analysed by combustion method. The mass of the $U$-tube increased by $1.08 \,g$. What is the percentage of hydrogen in the compound?
$1$-Butene and cyclobutane show
59 g of an amide obtained from a carboxylic acid, RCOOH, upon heating with alkali liberated 17 g of ammonia. The acid is
A compound with molecular formula $C_4H_4O$ has all the four carbon atoms and the oxygen atom inthe ring. It also has two double bonds. The compound is
A gas is found to have the formula (CO)$^n$. If its vapour density is 56, the value of n will be
A mixture of acetone (b.p. 56$^\circ$) and methanol (b.p. 65$^\circ$) can be separated by
A mixture of benzoic acid and naphthalene can be separated by crystallization from
A mixture of two immiscible liquids may be easily separated by using a
An example of alicyclic compound is
An organic compound contains $69\%$ carbon and $4.8\%$ hydrogen, the remainder being oxygen. What will be the masses of carbon dioxide and water produced when $0.20 \,g$ of this substance is subjected to complete combustion.
Aniline is insoluble in water and processes low vapour pressure. It can be purified by
Aniline is usually purified by
Arrange the following alkyl bromides in decreasing order of rates of $S_N2$ displacement reaction.
Bond length of ethane (I), ethene (II), acetylene (III) and benzene (IV) follows the order
$ C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}OH $ and $ {{H}_{3}}CC{{H}_{2}}OC{{H}_{3}} $ are: