Question

Many elements such as alkaline earths, which form refractory oxides require somewhat......
temperature for decomposition and for such elements .....is satisfactory.
da) higher, air-acetylene mixture (b) medium , air-coal gas inixture
(c) more, air-propane mixture (d) Icw, N2O-acetylene mixture​

Answer 1

Answer:

(c)...

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Answer 2

Answer:

lcw N20-acetylene mixture