What is the pH of 0.001 mol dm-3 solution of sodium hydroxide
14
13
12
11
Correct answer is D
\([H^+] [OH^-] = 10^{-14}\)
\([H^+] = 10^{-14}/[OH^-] = 10^{-14}/(1 * 10^{-3}) = 10^{-11}\)
pH = -Log10[H+]
= - Log10[10-11] = - 1 * -11 Log10[10-11] = 1 = -1 * -11 * 1 = 11
The uncovered raw food that is sold along major roads is likely to contain some amounts of
Pb
Cu
Ag
Na
Correct answer is A
The uncovered raw food that is sold along major roads is likely to contain some amounts of lead(Pb).
1.0
2.0
3.0
4.0
Correct answer is B
Relative molecular mass of NaCl = 23 + 35.5 = 58.5 g/mol
No. of mole of NaCl = 117/58.5 = 2.0 mol
The vulcanizer's solution is prepared by dissolving rubber in
ethanol
kerosine
benzene
petrol
Correct answer is C
Dissolved rubber in benzene makes the vulcanizer's solution.
When a few drops of water is added to a blue anhydrous cobalt (II) chloride, the colour changes to
white
pink
red
blue
Correct answer is B
Blue anhydrous cobalt (II) chloride changes to pink in water