Question

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

Answer 1

Answer:

d) low N20- acetylene mixture