An organic compound X give a red precipitate on heating with Fehling's solution. Which one of the following reactions yields X as a major product?
The spectrum of helium is expected to be similar to that of
The bond angle around O in ice is closer to
Which of the following is expected to be a paramagnetic complex?
The solubility in water of sulphates down the Be group is
Be>Mg>Ca>Sr>Ba. This is due to
An alkali metal (M) forms ion of the general formula
Which of the following arrangment for the three halogens Cl, Br and I when placed in the order of their increasing electron afffinity is correct?
Down the group, electron affinity decreases.(as with increase in size, tendency to hold electron decreases).
Gypsum, CaSO₄.2H₂O on heating to about 120oC, forms plaster of paris which has chemical composition represented by
'Z' in the following sequence of reactions is
Which of the following is not true in case of reaction with heated copper at 300oC?
Which is not the resonance structure of aniline?
A 500 g tooth paste sample has 0.2 g fluoride concentration. What is the concentration of F in terms of PPm level ?
PPM or Parts Per Million is expressed as 1 milligram of substance per kilogram of parent substance
Since, mass of toothpaste=500 g=0.5 kg, and
Mass of fluoride ion=0.2 g=200 mg
0.5 kg toothpaste contains 200 mg fluoride ions,
1 kg toothpaste will contain 200×2=400 mg fluoride ions
Hence, concentration of fluoride ion is 400 ppm