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A box of washing soda has 1.50 kg of $N{a}_{2}C{O}_3.10H_{2}O$ (molar mass = 286 g/mol). The box was sent to the godown and it weighed only 1.34 kg on arrival. An independent analyst says that the box contains the correct mass of sodium carbonate, but that it has lost the water of crystallization. What is the composition of the washing soda received by the godown?

Two radioactive element A and B have half - lives in the ratio of 1 : 2. If half - life A is 2 days, what will be the mole ratio of A to B after 12 days in a sample initially containing 1 mole of each ?

An ideal gas expands against a constant external pressure of $2.0$ atmosphere from $20$ litre to 40 litre and absorbs $10kJ$ of heat from surrounding. What is the change in internal energy of the system? (Given : 1 atm litre $=101.3J$)

In which of the following regioselectivity can be observed.

A balloon is filled with hydrogen at room temperature. It will burst if the pressure exceeds $5\text{bar}$. If at $1\text{bar}$ pressure the gas occupies $2.5\text{L}$, upto what volume can the balloon be compressed?

Which of the following expressions is correct for ‘$Ka$’ in terms of ${\Lambda }^{\circ }$ and $\Lambda$, where ‘$C$’ is the concentration.

$\begin{array}{cc}\text{List I}& \text{List II}\\ \text{1. Plaster of Paris}& \text{a.}CaS{O}_4.2H_{2}O\\ \text{2. Epsomite}& \text{b.}CaS{O}_4.1/2H_{2}O\\ \text{3. Kieserite}& \text{c.}MgS{O}_4.7H_{2}O\\ \text{4. Gypsum}& \text{d.}MgS{O}_4.H_{2}O\\ & \text{e.}CaS{O}_4\end{array}$

Which of the following is not a correct set of quantum numbers for an electron in an atom?

To raise the temperature of 1 mole of a diatomic gas by $1{}^{\circ }C$ at constant pressure, the required amount of heat is $120cal.$
The amount of heat which goes as the internal energy is almost equal to:

Two gases $A$ and $B$ present seperately in two vessels $X$ and $Y$ at the same temperature with molecular weights $M$ and $2M$ respectively are effused out. The orifice in vessel $X$ is circular while that in $Y$ is a square. If the radius of the circular orifice is equal to that of the length of the square orifice, the ratio of effusion of gas $A$ to that of gas $B$ is

The value of van der Waals' constant $a$ for various gases are given
$\begin{array}{cc}\text{Gas}& a\left(L^{2}atmmo{l}^{-2}\right)\\ N_2& 1.390\\ O_2& 1.360\\ N{H}_3& 4.170\\ C{H}_4& 2.253\end{array}$
The order of liquefaction of these gases is

Column-I: Property; Column-II: Variation of property; Column-III: Magnitude

$\begin{array}{cccccc}& \text{Column-I}& & \text{Column-II}& & \text{Column-III}\\ \text{(I)}& \text{Electron affinity}\left(E{A}_1\right)& \left(i\right)& \text{Decreases along the period}& \left(P\right)& \text{Highest in halogen in their respective periods}\\ \left(II\right)& \text{Ionization energy}\left(I{E}_1\right)& \left(ii\right)& \text{Directly proportional to}{Z}_{eff}& \left(Q\right)& \text{Highest in noble gases in their respective periods}\\ \left(III\right)& \text{Electronegativity}& \left(iii\right)& \text{Decreases down the group}& \left(R\right)& \text{Highest in alkali metals in their respective periods}\\ \left(IV\right)& \text{Electropositive character}& \left(iv\right)& \text{Inversly proportional to size}& \left(S\right)& \text{Moderate in noble gases in their respective periods}\end{array}$

The only correct combination for the energy involved during the gain of an electron is:

Define London forces

Is light really a wave, a ray or a stream of particles ?

Ethanol undergoes dehydration to form ethene by heating it with:

is the terminals of galvanic cell is just opposite in electrolytic cell and why

The value of b is how many times of the actual volume of the molecules:

Choose the correct decreasing order of the basic properties of oxides:

If $2.4088\times {10}^{26}$ electrons are there in a pure sample of $H_{2}S{O}_4$, then what is the mass of oxygen present?

Which of the following is the correct order of -I effect?

For the species $(I^{-},C{l}^{-},B{r}^{-})$, the increasing order of nucleophilicity in water would be:

Calculate the enthalpy change on freezing of 1.0 mol of water at ${10.0}^{\circ }C$ to ice at $-{10.0}^{\circ }C.\Delta fusH=6.03kJmo{l}^{-1}at{0}^{\circ }C$.
$\left(C_p\right[H_{2}O\left(l\right)]=75.3Jmo{l}^{-1}{K}^{-1}$
$C_p\left[H_{2}O\right(s\left)\right]=36.8Jmo{l}^{-1}{K}^{-1}$

Which of the following options has the incorrect order of stability?

The maximum number of compounds that have the same net dipole moment is?

$[thedipolemoment\mu ofC-Cl=1.5D]$

(1) $Ph-Cl$

(2)(3)

(4)(5)(6)

Which of the following is true regarding ideal solutions?

Why does the slowest step considered a rate determining step of the reaction?

Match the following:

How come water boils at a temperature below boiling point in hill stations?

At constant temperature, in a given mass of an ideal gas

Why Formic acid is more acidic than acetic acid.?

Conversion of $C{H}_4$ to $C{H}_{3}Cl$ is an example of which of the following reaction

Which one of the following ions will be smallest in size?

If heat of dissociation of $CHC{l}_{2}COOH$ is $0.7kcal/mole$ then $\Delta H$ for the reaction:

$CHC{l}_{2}COOH+KOH\to CHC{l}_{2}COOK+H_{2}O$

A balloon containing 1 mole air at 1 atm initially is filled further with air till pressure increases to 4 atm. The initial diameter of the balloon is 1 m and the pressure at each stage is proportion to diameter of the ballon. How many no. of moles of air added to change the pressure from 1 atm to 4 atm

2.0 moles of an ideal monoatomic gas is expanded isothermally from $10L$ to $20L$, at $27{}^{\circ }C$, against a constant external pressure of $0.1bar$. The correct changes in state parameters of gas in this process is/ are $[ln2=0.7,R=8.3J/K.mol]$

The vacant space in bcc lattice unit cell is

Why does the rate of a reaction increase with rising in temperature?