1
IIT-JEE 1978
Subjective
+4
-0
Igniting MnO2 converts it quantitatively to Mn3O4. A sample of pyrolusite is of the following composition : MnO2 80%, SiO2 and other inert constituents 15%, rest being water. The sample is ignited in air to constant weight. What is the percentage of Mn in the ignited sample? [O = 16, Mn = 54.9]
2
IIT-JEE 1978
Subjective
+4
-0
Naturally occurring boron consists of two isotopes whose atomic weighs are 10.01 and 11.01. The atomic weight of natural oron is 10.81. Calculate the percentage of each isotope in natural boron.
3
IIT-JEE 1978
Subjective
+2
-0
What is the molarity and molality of a 13% solution (by weight) of sulphuric acid with a density of 1.02 g/ml? To what volume should 100 ml of this acid be diluted in order to prepare a 1.5 N solution?
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