Describe the process of scouring of wool. Why is cool air passed over it after washing ?

After washing the wool ____ is passed over it to make it soften.

Assertion (A) : Scouring is the process of washing sheared fleece in hot water, detergent and alkali in tank Reason (R) : Scouring removes dirt, grass and grease

......... is the compound which can remove both nitrogen and oxygen of the air when it is passed over it at 1000^@C :

A student has two wires of iron and copper of equal length and diameter. He first joins two wires in series and passes an electric current through the combination which increases gradually. After that he joins two wires in parallel and repeats the process of passing current. Which wire will glow first in each case?

Dheeraj observed that the colour of walls of his house changes gradually into shiny white after white wash. He asked you, why did the colour changed into bright white. Predict the reason.

An electric toaster uses nichrome for its heating element. When a negligibly small current passes through it, its resistance at room temperature (27.0^(@)C) is found to be 75.3 Omega . When the toaster is connected to a 230 V supply, the current settles, after a few seconds, to a steady value of 2.68 A. what is the steady temperature of the nichrome element? The Temperature coefficient of resistance of nichrome averaged over the temperature range involved is 1.70 xx 10^(-4) .^(@)C^(-1) .

Electrolysis is the process in which electrical energy is converted to chemical energy. In electrolyte cell, oxidation takes place at anode and reduction at cathode. Electrode process depends on the electrode taken for electrolysis. Amount of substance liberated at an electrode is directly proportionation to the amount of charge passed through it. The mass of substance liberated at electrode is calculate using the following realation : m=(itE)/(96500) Here, E represent the equivalent mass and 96500 C is called the faraday constant. Faraday (96500 C) is the charge of 1 mole electron i.e., 6.023 xx 10^(23) electrons, it is used to liberate on gram equivalent of the substance. The platinum electrodes were immersed in a solution of cupric sulphate (CuSO_4) and electric current is passed through the solution. After sometimes, it was observed that the colour of copper sulphate disappeared with evolution of a gas at the electrode. The colourless solution contains.

The process ofcorrosion ofiron is known as rusting. Rust appears to be a hydrated ferricoxide Fe_2O_3, xH_2O, Both O_2 & H_2O are required for rusting. Iron can be protected from the rusting by use of following compounds. i) Applying paints, lacquers and enamells on the surface ofiron ii) By forming a firm and coherent protective coating of ferroroferric oxide. This is done by passing steam over hot iron iii) By coating a thin film of Zinc, Tin, Nickel, chromium, aluminium etc, on the surface of iron If plated with Zinc, the reaction of products of Zinc with O_2 and H_2O form a coating which sticks to the surface and there by protects iron Zinc protects iron from corrosion because

After washing ………….. is passed over the wool to make it softer.