Sign in
Please select an account to continue using cracku.in
↓ →
Join Our JEE Preparation Group
Prep with like-minded aspirants; Get access to free daily tests and study material.
It is observed that characteristic X-ray spectra of elements show regularity. When frequency to the power 'n' i.e. $$\nu^n$$ of X-rays emitted is plotted against atomic number Z, the following graph is obtained.
The value of 'n' is
Login to view the detailed solution.
Decreasing order of the hydrogen bonding in following forms of water is correctly represented by
A. Liquid water
B. Ice
C. Impure water
Login to view the detailed solution.
Order of Covalent bond;
A. KF > KI; LiF > KF
B. KF < KI; LiF > KF
C. SnCl$$_4$$ > SnCl$$_2$$; CuCl > NaCl
D. LiF > KF; CuCl > NaCl
E. KF < KI; CuCl > NaCl
.webp)
Match Column I with Column II
Column I Column II
A. Soda ash I. CaSO$$_4$$
B. Chlorophyll II. CaOH$$_2$$
C. Used in Whitewashing III. Na$$_2$$CO$$_3$$
D. Dentistry, ornamental work IV. Mg$$^{2+}$$ ions
Reaction of BeO with ammonia and hydrogen fluoride gives 'A' which on thermal decomposition gives BeF$$_2$$ and NH$$_4$$F. What is 'A'?
Increasing order of stability of the resonance structure is:
.webp)
Which of the following is true about freons?
Login to view the detailed solution.
In the depression of freezing point experiment
A. Vapour pressure of the solution is less than that of pure solvent
B. Vapour pressure of the solution is more than that of pure solvent
C. Only solute molecules solidify at the freezing point
D. Only solvent molecules solidify at the freezing point
Login to view the detailed solution.
Statement I: For colloidal particles, the values of colligative properties are of small order as compared to values shown by true solutions at same concentration.
Statement II: For colloidal particles, the potential difference between the fixed layer and the diffused layer of same charges is called the electrokinetic potential or zeta potential.
In the light of the above statements, choose the correct answer from the options given below:
Login to view the detailed solution.
.webp)
Match List I with List II.
List I List II
A. Reverberatory furnace I. Pig iron
B. Electrolytic cell II. Aluminium
C. Blast furnace III. Silicon
D. Zone refining furnace IV. Copper
Login to view the detailed solution.
An ammoniacal metal salt solution gives a brilliant red precipitate on addition of dimethylglyoxime. The metal ion is:
Login to view the detailed solution.
Which of the Phosphorus oxoacid can create silver mirror from AgNO$$_3$$ solution?
Login to view the detailed solution.
.webp)
The magnetic moment of a transition metal compound has been calculated to be 3.87 BM. The metal ion is
Login to view the detailed solution.
The primary and secondary valencies of cobalt respectively in Co(NH$$_3$$)$$_5$$ClCl$$_2$$ are:
Login to view the detailed solution.
Assertion A: Hydrolysis of an alkyl chloride is a slow reaction but in the presence of NaI, the rate of hydrolysis increases.
Reason R: I$$^-$$ is a good nucleophile as well as a good leaving group.
In the light of the above statements, choose the correct answer from the options given below:
Login to view the detailed solution.
In the following given reaction 'A' is
'A' and 'B' formed in the following set of reactions are:
'R' formed in the following sequence of reaction is:
_1.webp)
Compound X undergoes following sequence of reactions to give the Lactone Y.
Given below are two statements:
Statement I: Noradrenaline is a neurotransmitter.
Statement II: Low level of noradrenaline is not the cause of depression in human.
In the light of the above statements, choose the correct answer from the options given below:
Login to view the detailed solution.
If wavelength of the first line of the Paschen series of hydrogen atom is 720 nm, then the wavelength of the second line of this series is _____ nm. (Nearest integer)
Login to view the detailed solution.
For independent process at 300 K.
| Process | $$\Delta H$$ / kJmol$$^{-1}$$ | $$\Delta S$$ / JK$$^{-1}$$ |
|---|---|---|
| A | -25 | -80 |
| B | -22 | 40 |
| C | 25 | -50 |
| D | 22 | 20 |
Login to view the detailed solution.
The dissociation constant of acetic is $$x \times 10^{-5}$$. When 25 mL of 0.2 M CH$$_3$$COONa solution is mixed with 25 mL of 0.02 M CH$$_3$$COOH solution, the pH of the resultant solution is found to be equal to 5. The value of $$x$$ is _____.
Login to view the detailed solution.
Uracil is base present in RNA with the following structure. % of N in uracil is _____.
Login to view the detailed solution.
When Fe$$_{0.93}$$O is heated in presence of oxygen, it converts to Fe$$_2$$O$$_3$$. The number of correct statement/s from the following is _____.
A. The equivalent weight of Fe$$_{0.93}$$O is $$\frac{\text{Molecular weight}}{0.79}$$
B. The number of moles of Fe$$^{2+}$$ and Fe$$^{3+}$$ in 1 mole of Fe$$_{0.93}$$O is 0.79 and 0.14 respectively.
C. Fe$$_{0.93}$$O is metal deficient with lattice comprising of cubic closed packed arrangement of O$$^{2-}$$ ions.
D. The % composition of Fe$$^{2+}$$ and Fe$$^{3+}$$ in Fe$$_{0.93}$$O is 85% and 15% respectively.
Login to view the detailed solution.
5 g of NaOH was dissolved in deionized water to prepare a 450 mL stock solution. What volume (in mL) of this solution would be required to prepare 500 mL of 0.1 M solution? Given: Molar Mass of Na, O and H is 23, 16 and 1 g mol$$^{-1}$$ respectively
Login to view the detailed solution.
At 298 K, a 1 litre solution containing 10 mmol of Cr$$_2$$O$$_7^{2-}$$ and 100 mmol of Cr$$^{3+}$$ shows a pH of 3.0. Given: Cr$$_2$$O$$_7^{2-} \to$$ Cr$$^{3+}$$; E$$^0 = 1.330$$ V and $$\frac{2.303RT}{F} = 0.059$$ V. The potential for the half cell reaction is $$x \times 10^{-3}$$ V. The value of $$x$$ is _____.
Login to view the detailed solution.
The number of correct statement/s from the following is _____.
A. Larger the activation energy, smaller is the value of the rate constant.
B. The higher is the activation energy, higher is the value of the temperature coefficient.
C. At lower temperatures, increase in temperature causes more change in the value of k than at higher temperature.
D. A plot of ln k vs $$\frac{1}{T}$$ is a straight line with slope equal to $$\frac{-E_a}{R}$$
Login to view the detailed solution.
The d-electronic configuration of CoCl$$_4^{2-}$$ in tetrahedral crystal field is $$e^m t_2^n$$. The sum of m and number of unpaired electrons is
Login to view the detailed solution.
Number of moles of AgCl formed in the following reaction is _____.
Educational materials for JEE preparation
Share
