List of practice Questions

Given below are two statements:
Statement I : In froth floatation method a rotating paddle agitates the mixture to drive air out of it.
Statement II : Iron pyrites are generally avoided for extraction of iron due to environmental reasons.
In the light of the above statements, choose the correct answer from the options given below:
A. Ammonium salts produce haze in atmosphere 
B. Ozone gets produced when atmospheric oxygen reacts with chlorine radicals
C. Polychlorinated biphenyls act as cleansing solvents 
D. 'Blue baby' syndrome occurs due to the presence of excess of sulphate ions in water 
Choose the correct answer from the options given below:
Given below are two statements, one is labelled as Assertion $A$ and the other is labeled as Reason $R$ 
Assertion A : The alkali metals and their salts impart characteristic colour to reducing flame 
Reason R : Alkali metals can be detected using flame tests 
In the light of the above statements, choose the most appropriate answer from the options given below
Given below are two statements, one is labelled as Assertion $A$ and the other is labelled as Reason $R$
Assertion A: Carbon forms two important oxides - $CO$ and $CO _2 .CO$ is neutral whereas $CO _2$ is acidic in nature
Reason R : $CO _2$ can combine with water in a limited way to form carbonic acid, while $CO$ is sparingly soluble in water
In the light of the above statements, choose the most appropriate answer from the options given below
Match List I with List II :
List-I Coordination entityList-II Wavelength of light absorbed in nm
A.\([CoCl(NH_3​)_5​]^{2+}\)I.310
B.\([Co(NH_3​)_6​]^{3+}\)II.475
C.\([Co(CN)_6​]^{3−}\)III.535
D.\([Cu(H_2​O)_4​]^{2+}\)IV.600
Choose the correct answer from the options given below :
What is the mass ratio of ethylene glycol \((C _2H _6O_2\), molar mass \(62\ g/mol)\) required for making \(500\ g\) of \(0.25\) molal aqueous solution and \(250\ ml\) of \(0.25\) molal aqueous solution?
Which one among the following metals is the weakest reducing agent?
When the hydrogen ion concentration $\left[ H ^{+}\right]$changes by a factor of $1000$ , the value of $pH$ of the solution_____

A bowl filled with very hot soup cools from $98^{\circ} C$ to $86^{\circ} C$ in 2 minutes when the room temperature is $22^{\circ} C$. How long it will take to cool from $75^{\circ} C$ to $69^{\circ} C$ ?

In an LC oscillator, if values of inductance and capacitance become twice and eight times, respectively, then the resonant frequency of oscillator becomes $x$ times its initial resonant frequency $\omega_0$ The value of $x$ is:
A solenoid of $1200$ tums is wound uniformly in a single layer on a glass tube $2\, m$ long and $02\, m$ in diameter The magnetic intensity at the center of the solenoid when a current of $2 A$ flows through it is:

Compound A reacts with $NH _4 Cl$ and forms a compound B.

Compound B reacts with $H _2 O$ and excess of $CO _2$ to form compound $C$ which on passing through or reaction with saturated $NaCl$ solution forms sodium hydrogen carbonate Compound $A , B$ and $C$, are respectively.

The correct order in aqueous medium of basic strength in case of methyl substituted amines is :
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason $R$:
Assertion A: Acetal / Ketal is stable in basic medium
Reason R: The high leaving tendency of alkoxide ion gives the stability to acetal ketal in basic medium
In the light of the above statements, choose the correct answer from the options given below :
Which one of the following reactions does not occur during extraction of copper?

A cubic solid is made up of two elements $X$ and $Y$ Atoms of $X$ are present on every alternate corner and one at the enter of cube $Y$ is at $\frac{1}{3} td$ of the total faces The empirical formula of the compound is

The mean and variance of the marks obtained by the students in a test are 10 and 4 respectively Later, the marks of one of the students is increased from 8 to 12 If the new mean of the marks is $10.2$, then their new variance is equal to :

If $a_r$ is the coefficient of $x^{10-r}$ in the Binomial expansion of $(1+x)^{10}$, then $\displaystyle\sum_{r=1}^{10} r^3\left(\frac{a_r}{a_{r-1}}\right)^2$ is equal to

Let $f:(0,1) \rightarrow R$ be a function defined by

$f(x)=\frac{1}{1-e^{-x}}$, and $g(x)=(f(-x)-f(x))$ Consider two statements

(I) $g$ is an increasing function in $(0,1)$

(II) $g$ is one-one in $(0,1)$Then,

Let $z_1=2+3 i$ and $z_2=3+4 i$. The set $S=\left\{z \in C:\left|z-z_1\right|^2-\left|z-z_2\right|^2=\left|z_1-z_2\right|^2\right\}$ represents a

Let $y (x)=(1+x)\left(1+x^2\right)\left(1+x^4\right)\left(1+x^8\right)\left(1+x^{16}\right)$. Then $y^{\prime}-y^{\prime \prime}$ at $x=-1$ is equal to :

Let $M$ be the maximum value of the product of two positive integers when their sum is 66. Let the sample space $S =\left\{x \in Z : x(66-x) \geq \frac{5}{9} M\right\}$ and the event $A =\{x \in S : x$ is a multiple of 3$\}$. Then $P ( A )$ is equal to

Consider the lines $L_1$ and $L_2$ given by 

$L_1: \frac{x-1}{2}=\frac{y-3}{1}=\frac{z-2}{2} $ 

$ L_2: \frac{x-2}{1}=\frac{y-2}{2}=\frac{z-3}{3}$

A line $L_3$ having direction ratios $1,-1,-2$, intersects $L_1$ and $L_2$ at the points $P$ and $Q$ respectively Then the length of line segment $P Q$ is

The points of intersection of the line $a x+b y=0,(a \neq b)$ and the circle $x^2+y^2-2 x=0$ are $A (\alpha, 0)$ and $B (1, \beta)$ The image of the circle with $AB$ as a diameter in the line $x+y+2=0$ is :

The vector $\vec{a}=-\hat{i}+2 \hat{j}+\hat{k}$ is rotated through a right angle, passing through the y-axis in its way and the resulting vector is $\vec{b}$. Then the projection of $3 \vec{a}+\sqrt{2} \vec{b}$ on $\vec{c}=5 \hat{i}+4 \hat{j}+3 \hat{k}$ is :