Class 12th

ANSWER: Given compound is having 8 carbons, and on reaction with chromic acid C is converted back into B, as chromic acid reaction couldn't add any carbon hence both alcohol and acid must contain 4 carbons and it is given in the question that on dehydration C will give but-1-ene so alcohol will be butan-1-ol (C) and acid will be butan-1-oic acid (B) and given reaction will be ester hydrolysis,

 

The image is real when it is formed by the actual convergence of rays and it can be projected on a screen. For example, when the object is placed beyond focus, and the image is formed either by the convex lens or concave mirror.
The image is virtual, if it is formed by the apparent divergence of rays and it cannot be captured on a screen. For example, when the image is formed by the convex mirror or plane mirror.

Since the given compound with molecular formula C₉H₁₀O form a 2,4-DNP derivative and reduce Tollen's reagent, it must be an aldehyde. Since it undergoes cannizzaro reaction, therefore CHO group is directly attached to the benzene ring.

Since on vigorous oxidation, it gives 1,2-benzene dicarboxylic acid, therefore it must be ortho-substituted benzaldehyde. The only o-substituted aromatic aldehyde having molecular formula C₉H₁₀O is o—ethyl benzyldehyde all the reaction can show now be explained on the basis of this structure-

Simple microscope: When the object is placed within the focal length, the simple microscope works on the principle of producing an erect, virtual and magnified image. To magnify small objects, the simple microscope uses a single convex lens.
Compound microscope: It uses two lenses including an eyepiece and objective. The objective lens creates a real, magnified, and inverted image which acts as the object for the eyepiece, which in turn magnifies it further.

i) Taking two molecules of propanal, one which acts as a nucleophile and the other as an electrophile.

(iii) Taking one molecule each of propanal and butanal in which propanal acts as a nucleophile and butanal acts as an electrophile.

 

In Ray Optics And Optical Instruments questions, when using lens and mirror formulas, sign convention helps in maintaining consistency. The sign convention determines whether quantities like image distance, object distance, and focal length are taken as positive or negative. The incorrect usage of these sign conventions mostly leads to wrong magnifications and image positions. For accurate results, it is essential to follow the Cartesian sign.

1. Butane-1,3-diol -

Ethanol react dilute alkali produces 3-hydroxybutanal which on Reduction gives butane-1, 3-diol on reduction.