Acidified potassium dichromate oxidizes sulphides (S^2-) to __________

The correct decreasing order of basic strength of following amines in aqueous medium is.
(A) \((C_2H_5)_3N\)
(B) \((C_2H_5)_2NH\)
(C) \(C_2H_5NH_2\)
(D) \(NH_3\)
Choose the \textbf{correct} answer from the options given below:

Read the passage carefully and answer the questions
Amines are considered as derivatives of ammonia obtained by replacement of hydrogen atoms with alkyl or aryl groups. In nature they occur among proteins, vitamins, alkaloids and hormones. These can be primary, secondary or tertiary depending on the number of hydrogen groups replaced. They can be prepared from nitro compounds, alkyl halides, nitriles, amides etc. Due to unshared pair of electrons they behave as Lewis bases. Influence of the number of hydrogen atoms at nitrogen atom is displayed in physical properties such as solubility, boiling point and chemical reactions including basicity. Basic character of amines is expressed in terms of their \(K_b\) and \(p K_b\) values. Three classes of amines can be distinguished with p-toluene sulphonyl chloride which reacts with primary and secondary ddu amines. Amino group when attached to benzene ring behaves as an activating and ortho para directing group.
Which of the following is a tertiary amine?

Consider the following reaction:
\(Ph-CH(Cl)-CH_3 \xrightarrow[\Delta]{\text{ alc. } KCN}\text {?}\)
The product formed is:

Salicylaldehyde is formed as a main product from phenol by :

The magnetic behaviour of manganate ion and permanganate ions, respectively, are

For strong electrolytes, \(\Lambda_m\) increases with dilution and is represented by the equation \(\Lambda_m=\Lambda_m^0-A c^{1 / 2}\). Here, the
(A) Nature of solvent.
(B) Temperature.
(C) Charges on cation and anions produced.
(D) Type of electrolyte.
Choose the correct answer from the options given below :

A spherical ice ball is melting at the rate of \(100 \pi \mathrm{~cm}^3 / \mathrm{min}\). The rate at which its radius is decreasing when its radius is 15 cm, is

In a Wheatstone bridge, the resistances \( R_1, R_2, R_3 \) and \( R_4 \) present in four arms are \( 10 \Omega, 30 \Omega, 30 \Omega \) and \( 90 \Omega \) respectively. If the galvanometer resistance is \( 50 \Omega \) and the voltage of the battery is 7 V and its internal resistance is \( 5 \Omega \), then the total current drawn from the battery is

Two percent of the bolts manufactured in a factory are found to be defective. Using the Poisson distribution, the probability that in a sample of 100 bolts chosen at random, exactly two will be defective, is : [Given \(e^{-2}=0.135\)]

If \(x\) is real, the minimum value of \(x^2-8 x+20\) is :

Which among the following is not a broad spectrum antibiotic?

The slope of the normal to the curve \(y=2 x^2\) at \(x=1\) is: