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Starting from benzenesulphonic acid, what is the intermediate formed before acidification to yield phenol?
The NCERT text says: 'Benzene is sulphonated with oleum and benzene sulphonic acid so formed is converted to sodium phenoxide on heating with molten sodium hydroxide. Acidification of the sodium salt gives phenol.'
Diazonium salts for phenol preparation are formed by treating an aromatic primary amine with which of the following reagents?
The NCERT text states: 'A diazonium salt is formed by treating an aromatic primary amine with nitrous acid (NaNO2 + HCl) at 273-278 K.'
The preparation of phenol in the laboratory is typically carried out from which type of compounds, as mentioned in the NCERT text?
The NCERT text states: 'In the laboratory, phenols are prepared from benzene derivatives by any of the following methods.'
Which of the following organic functional groups is characteristic of both alcohols and phenols?
The introductory part of the chapter mentions: 'Alcohols and phenols are formed when a hydrogen atom in a hydrocarbon, aliphatic and aromatic respectively, is replaced by –OH group.'
Phenol was first isolated from which natural source in the early nineteenth century?
The NCERT text states: 'Phenol, also known as carbolic acid, was first isolated in the early nineteenth century from coal tar.'
Which of the following insect groups is NOT typically targeted by Bt toxin produced from Bacillus thuringiensis?
The context states, 'Some strains of Bacillus thuringiensis produce proteins that kill certain insects such as lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).' Hymenopterans are not mentioned as a target group.
The Bt toxin protein exists as an inactive protoxin within Bacillus thuringiensis. What condition in the insect gut is responsible for its activation?
According to the text, 'the Bt toxin protein exist as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals.'
What is the primary mechanism by which activated Bt toxin kills the insect?
The context clearly states, 'The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of the insect.'
Which of the following genes controls cotton bollworms?
The NCERT text mentions, 'The proteins encoded by the genes $cryIAc$ and $cryIIAb$ control the cotton bollworms'.
Why does the Bt toxin not kill the Bacillus thuringiensis bacteria that produce it?
The text explains, 'Why does this toxin not kill the Bacillus? Actually, the Bt toxin protein exist as inactive protoxins...'
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The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.