Will 2, 10kA breakers for stove requiring a 50 Amp breaker
"10KA" means 10,000 amps.  Is is an extreme conditions rating for the breaker.  It means that if your range suddenly has a massive problem, and causes a dead short, causing thousands of amps to flow, the breaker is certified to be able to interrupt it if it's less than 10,000 Amps.  If it's 20,000 amps, the breaker might not be able to interrupt it.  Some power companies claim to intentionally use thin enough wire or small enough transformers that 10,000 amps is impossible.  

So it's sort of like the ZR rating on your tires, the tire won't explode if you drive 185 miles per hour.  

You can't use two singles on a range

You can't use 30A+ singles for anything, really.   

However if you got a factory made "handle-tie" to tie them together, you still wouldn't be able to use them for a range, because it is a 120/240V load that uses a neutral wire.   

You would be able to use them (handle-tied) for certain other large loads, such as heat pump emergency heat, on demand water heater, etc. which do not require neutral.  

So sell them on eBay and get a 2-pole.  Expect to pay $10 (unless they're GFCI, AFCI etc.,  however if they were, you can't use singles at all).